National Health Interview Survey/
National Immunization Provider Record
Check Study
User=s Guide for the
1997 Public-Use Data File
Prepared for
U.S. Department of Health and Human Services
Centers for Disease Control and Prevention
National Center for Health Statistics
and
National Immunization Program
Prepared by
Abt Associates Inc.
September 2002
2
Table of Contents
Appendices.......................................................................................................................................3
Glossary of Commonly Used Terms and Abbreviations .................................................................4
Chapter 1. Introduction...................................................................................................................5
Chapter 2. Sample and Data Collection..........................................................................................8
2.1 Summary of 1997 Sample.............................................................................................8
2.2 NHIS Immunization Supplement................................................................................10
2.3 National Immunization Provider Record Check Study..............................................10
2.3.1 Original Data Collection..............................................................................10
2.3.2 Matching and Reconciliation.......................................................................12
2.4 Data Processing ..........................................................................................................16
2.5 Informed Consent, Security, and Confidentiality of Information ..............................17
Chapter 3. Estimation of Vaccination Coverage...........................................................................18
3.1 NHIS Weighting Information.....................................................................................18
3.2 Provider-Adjusted Estimates .....................................................................................18
3.3 Adjustment for Effect of Nonresponse Follow-Up Survey........................................18
3.4 Best Values .................................................................................................................19
3.5 Best Value Weights.....................................................................................................20
3.6 Imputed Best Values ...................................................................................................21
3.7 Children Aged 12-18 months ......................................................................................22
Chapter 4. Calculating Estimates of Vaccination Coverage and Standard Errors ........................23
4.1 Provider-Adjusted Estimates of Vaccination Coverage .............................................23
4.2 Including the Nonresponse Follow-Up Survey Adjustment in Coverage Estimates..25
4.3 Best Value Estimates and Using Imputed Best Values ..............................................26
4.4 Calculating Standard Errors........................................................................................26
4.4.1 Standard Errors of NHIS Estimates ............................................................26
4.4.2 Standard Errors of Best Value Estimates ....................................................26
4.4.3 Standard Errors of Estimates Based on Imputed Best Values ....................27
Chapter 5. Public-Use Data File ...................................................................................................28
5.1 File Description...........................................................................................................28
5.2 Data Cleaning..............................................................................................................28
5.3 Missing Value Codes ..................................................................................................29
5.4 Variable Naming Conventions....................................................................................29
5.5 Explanatory Notes for Specific Variables...................................................................30
5.6 Flags............................................................................................................................32
5.7 Data Alerts ..................................................................................................................32
5.8 Code Book...................................................................................................................33
5.9 Guidelines for Citation of Data...................................................................................33
References......................................................................................................................................34
3
Appendices
Appendix A Estimates of Vaccination Coverage Rates among Children Aged 19-35
Months
Appendix B 1997 NHIS/NIPRCS Immunization History Questionnaire
Appendix C Estimates of Vaccination Coverage among Children Aged 12-18 Months
Appendix D Weighting Classes and Calculations for Provider-Adjusted Estimates
Appendix E Example of a SAS Program That Calls SUDAAN for Calculating Standard
Errors
Appendix F Unweighted Distribution of Children Aged 12-35 Months in the 1997
NHIS/NIPRCS by Selected Demographic Characteristics
Appendix G Weighted Distribution of Children Aged 12-35 Months in the 1997
NHIS/NIPRCS by Selected Demographic Characteristics
Appendix H Descriptive Statistics for Two Sampling Weight Variables Included in the
1997 NHIS/NIPRCS Data File
4
Glossary of Commonly Used Terms and Abbreviations
4:3:1 Child has received 4 or more DTP, 3 or more polio, and 1 or more MCV
vaccinations.
4:3:1:3 Child has received 4 or more DTP, 3 or more polio, 1 or more MCV, and 3 or
more Hib vaccinations.
4:3:1:3:3 Child has received 4 or more DTP, 3 or more polio, 1 or more MCV, 3 or more
Hib, and 3 or more hepatitis B vaccinations.
CAPI Computer-assisted personal interviewing
CDC Centers for Disease Control and Prevention
DTaP Diphtheria, tetanus, acellular pertussis
DTP Diphtheria, tetanus, pertussis
Hep B Hepatitis B
Hib Haemophilus influenzae type b
IHQ Immunization History Questionnaire
IPV Inactivated poliovirus vaccine
MCV Measles-containing vaccine
MMR Measles, mumps, rubella
NCHS National Center for Health Statistics
NHIS National Health Interview Survey
NHIS/IM National Health Interview Survey Immunization Supplment
NIP National Immunization Program
NIPRCS National Immunization Provider Record Check Study
NRFUS Nonresponse Follow-Up Survey
OPV Oral poliovirus vaccine
5
Chapter 1. Introduction
Since 1991, national estimates of vaccination coverage have been available through the National
Health Interview Survey - Immunization Supplement (NHIS/IM), sponsored by the National
Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (CDC)
and conducted by the Census Bureau. The NHIS questionnaire includes a core module that
collects demographic information on all household members, a module of health questions about
one sampled adult, and a module of health questions about one sampled child.
1
At the end of the
core interview, the NHIS/IM is administered for the sampled child and all other children in the
household between the ages of 12 and 35 months. (In the first half of 1997, immunization data
were collected only for non-sample children aged 19-35 months. Children aged 12-18 months
were added to the survey in the third quarter of data collection.) The NHIS/IM asks for a
vaccination history of the child. Respondents can either report vaccination dates from a written
shot record, if one is available for the child, or they can report the total number of doses for each
vaccine from memory recall if no shot record is available.
Reliance on household reports of childhood immunizations has two potential inaccuracies that
influence the estimation of vaccination coverage (Zell et al. 1996). First, a large proportion
(63%) of respondents rely only on memory recall to report their child's immunization history,
which is subject to the potential bias inherent in recall data. In 1997, only 37% of respondents
used a shot card to report all or some of their child's vaccinations. Second, even when shot
records are used, dates of vaccinations may be missing if the respondent did not have the shot
record at the time of the immunization or the original shot record has been lost. Thus, the
validity of the vaccination coverage estimates produced from the NHIS has been a major
concern. Therefore, to determine the accuracy of the household responses in the NHIS, the
NCHS and the National Immunization Program (NIP) of the CDC implemented the National
Immunization Provider Record Check Study (NHIS/NIPRCS) in 1994. Its purpose is to evaluate
the accuracy of household reports of children’s immunization histories by comparing the
household reports with the reports from the children's immunization providers, and to produce
national estimates of vaccination coverage using both the household and provider reports
(Ezzati-Rice et al. 1996; Peak and Cadell 1996). The estimates of vaccination coverage from the
NHIS/NIPRCS are also used to adjust for non-telephone coverage bias in the National
Immunization Survey (NIS), a telephone survey of households with children aged 19-35 months.
1
For details on the NHIS sample design and data collection procedures, see the documentation on the NHIS Web site:
http://www.cdc.gov/nchs/nhis.htm
6
The NHIS/NIPRCS produces estimates of coverage for nine vaccines and series of vaccines.
Table 1.1 lists these vaccines and the number of doses required to be up-to-date for each vaccine
and series.
Table 1.1: Vaccines and Combinations of Vaccines Monitored in the
1997 NHIS/NIPRCS
DTP 4 or more doses of diphtheria-tetanus-pertussis vaccine
DTP3 3 or more doses of diphtheria-tetanus-pertussis vaccine
Polio 3 or more doses of polio vaccine
MCV 1 or more doses of measles-containing vaccine
Hib 3 or more doses of Haemophilus influenzae type b vaccine
Hep B 3 or more doses of hepatitis B vaccine
4:3:1 4 or more doses of DTP, 3 or more doses of polio, and 1 or more
doses of measles-containing vaccine
4:3:1:3 4 or more doses of DTP, 3 or more doses of polio, 1 or more doses
of measles-containing vaccine, and 3 or more doses of Hib vaccine
4:3:1:3:3
4 or more doses of DTP, 3 or more doses of polio, 1 or more doses
of measles-containing vaccine, 3 or more doses of Hib, and 3 or
more doses of hepatitis B vaccine
General Information about the 1997 NHIS/NIPRCS
The NHIS/NIPRCS begins with households that completed an NHIS/IM for a child or children
aged 12-35 months (or 19-35 months in the first half of 1997). As part of completing the
Immunization Supplement, the parent or legal guardian is asked to sign a permission form
allowing the survey staff to contact the child's medical providers. Only households that signed
permission forms are eligible for the NHIS/NIPRCS. The permission form has space for the
names and addresses of up to three providers. It also contains identifying information and the
signature of the parent or guardian. Permission forms are valid for one year from the date of the
interview. The permission forms are sent to the NHIS/NIPRCS contractor for data collection,
Abt Associates Inc.
All providers for whom households gave adequate locating information are mailed an
Immunization History Questionnaire (IHQ). (See Appendix B for a copy of the 1997 IHQ.) A
label on the IHQ gives the child's name, date of birth, and gender, so the provider can locate the
child's records. The form includes a grid for the provider to record the date of each vaccination
the child has received. The provider is asked to enter all known vaccinations, whether they were
given at that practice or elsewhere. In addition to the child's immunization history, the form
collects characteristics of the provider's practice, such as whether the practice is a public or
private facility and the types of care provided.
The returned IHQs are reviewed for legibility and consistency, and edited as appropriate before
being sent to a vendor for data entry. The data from the IHQ are entered in a database, with
7
100% double-keying, and the raw data file is returned to the contractor for cleaning and further
editing.
The immunization information reported by the households and providers is compared for each
child. If discrepancies are discovered, the case is eligible for reconciliation. That process
contacts the providers, the household, or both to resolve the inconsistencies between the reports.
The household is asked to verify some information and whether any additional providers should
be contacted, and the providers are asked about specific vaccination dates or whether another
provider could have immunization records for the child. If discrepancies remain in the data after
these contacts, either the provider information or a combination of the household and provider
information is considered to be the most accurate or the “best values” for immunization
information.
The NHIS interviews were conducted between January and December of 1997. Due to an error
in the computerized questionnaire, permission forms were not generated for some children
eligible for the provider record check. An effort to recontact these households to obtain
permission forms was conducted by the Census Bureau in 1998. Data collection for the 1997
NHIS/NIPRCS began in May 1999 and continued through April 2000. Original permission
forms that were more than one year old were renewed in December 1999 and January 2000.
Reconciliation was conducted between May and September of 2000.
The 1997 NHIS/NIPRCS public-use data file (PUF) includes data for 2,622 children with
completed NHIS/IM interviews. The variables included in the file come from the 1997 NHIS
and the 1997 NHIS/NIPRCS IHQ. The NHIS variables were selected from the following NHIS
data files: Household, Family, Person, Sample Adult, Sample Child, and Immunization
Supplement.
For further information on the NHIS data products, please contact the NCHS Data Dissemination
Branch:
Phone: 301-458-4901
FAX: 301-458-4035
E-mail: [email protected]
Internet: http://www.cdc.gov/nchs/nhis.htm
8
Chapter 2. Sample and Data Collection
2.1 Summary of 1997 Sample
The 1997 NHIS/NIPRCS sample contains 2,622 children aged 12-35 months with a completed
NHIS/IM. Of these children, 462 (17.6%) were aged 12-18 months at the time of the NHIS
interview, and 2,160 (82.4%) were 19-35 months. IHQs were mailed to the providers for the
1,141 children (43%) who had valid original or renewed permission forms. Providers returned
IHQs with vaccination data for 1,074 (94%) of the children. Approximately 41% of the
children with a completed NHIS/IM had provider data. (See Figure 2.1.)
Of the 2,622 children, best values for vaccination dates could be determined for 1,197 (45.7%).
The number of children with best values for vaccination dates is greater than the number of
children with provider vaccination data. Some children without provider vaccination data have
best vaccination values because they are 4:3:1:3 up-to-date from a household shot card. For the
children without best values, up-to-date status was imputed. (The imputation procedures are
described in Section 3.6.) Table 2.1 shows the results of the provider data collection and best
value construction for the two age groups. See Appendices F and G for tables summarizing the
distribution of the sample by various demographic characteristics.
Table 2.1: Distribution of Children with Provider and Best Value Data by Age
Group, 1997 NHIS/NIPRCS
Children aged
12-18 months
Children aged
19-35 months
Total
Total number of children
462
2,160
2,622
Number of children with
requests mailed to providers
n/a
n/a
1,141
Number of children with
provider data
173
901
1,074*
Number of children with
best values
177
1,020
1,197
Number of children with
imputed best values
285
1,140
1,425
*After reconciliation, the number of cases with provider data went down from 1082 to 1074. See Footnote 2 for
Table 2.2 for an explanation of these procedures.
9
TOTAL CHILDREN
WITH NHIS/IM
2,622
MATCHED PERMISSION FORMS
1,410
NO PERMISSION
FORM
1,212
MAILED IHQ TO PROVIDERS
1,141
RECEIVED IHQ
1,054
NO IHQ
87
UNUSABLE FORMS
Refusals = 45
No provider = 153
FIGURE 2.1: 1997 NHIS/ NIPRCS SAMPLE
FINAL NON-
RENEWALS
71
PERMISSION FORM
RENEWED
89
VALID PERMISSION
FORMS
1,052
IHQ RECEIVED IN
RECONCILIATION
20
WITH PROVIDER DATA
1,074
NO
RECONCILIATION
67
10
2.2 NHIS Immunization Supplement
The U.S. Bureau of the Census collects data for the NHIS under a contract with the NCHS.
Census Bureau interviewers conduct personal, in-home interviews with individuals in sampled
households. For the Family Core component of the NHIS Basic Module, all members of an
eligible household who are at home at the time of the interview and 17 years of age and over are
asked to participate and to respond for themselves. For children and those adults not at home
during the interview, information is provided by a knowledgeable adult family member (18 years
of age or over) residing in the household. For the Sample Adult questionnaire, one adult per
family is randomly selected; this individual responds for him/herself to the questions in this
interview. Information for the Sample Child questionnaire is obtained from a knowledgeable
adult in the household.
The 1997 NHIS interview was conducted using a computer-assisted personal interviewing
(CAPI) version of the NHIS questionnaire. Interviewers administered the instrument using
laptop computers, entering responses directly into the computer during the household interview.
This computerized mode of administration offers distinct advantages in timeliness of the data
and improved data quality.
The data for the NHIS/IM are collected for children selected for the Sample Child questionnaire,
and all other children in the household between the ages of 12 and 35 months. (In the first two
quarters of 1997, NHIS/IM data were collected only for children between the ages of 19 and 35
months. Children between the ages of 12 and 18 months were added in the third quarter of data
collection.)
2.3 National Immunization Provider Record Check Study
The data in the provider record check study are collected in two phases: original data collection
and reconciliation. In the original data collection, immunization records are collected from the
providers. In reconciliation, the data collected from the providers are compared and reconciled
with the data collected from the household. During reconciliation, some new IHQs are received
for children for whom provider data were not obtained in the original data collection.
2.3.1 Original Data Collection
Once the NHIS/IM is completed, the names and addresses of immunization providers identified
by household respondents are written on permission forms. The NHIS CAPI questionnaire
captures whether a permission form was completed (or Agenerated@), and whether the permission
form was signed by the child=s parent or legal guardian. An electronic file of eligible household
ID numbers with child and household data is forwarded to the NHIS/NIPRCS contractor, Abt
Associates, where it is entered into a case management and tracking system. The Regional
Offices of the Census Bureau send the signed permission forms to the contractor.
The first step in data collection matches the permission forms with the file of eligible
households. The file is loaded into a case management system. After the forms have been
11
matched, provider names, addresses and telephone numbers are entered from the hard-copy
permission forms. After data entry and editing are completed, a scannable label with an ISBN
bar code is printed for each case ID and attached to the appropriate permission form in order to
facilitate tracking and reporting.
Once the provider address information has been entered, the next step is to check its
completeness. (Complete addresses are necessary to mail questionnaires to immunization
providers.) When the household did not supply a complete address for a provider, locating clerks
use multiple methods to find additional information, including searching a database of providers
from the NIS and calling Directory Assistance.
Once the provider addresses have been reviewed and updated, the initial requests are mailed.
The initial mailing packet includes the following documents:
$ A cover letter from the Director of the NCHS describing the purpose of the
NHIS/NIPRCS, the importance of provider participation, and how the parent=s
consent was obtained. Separate letters are used for cases with a parent=s signature
and cases with an interviewer=s signature verifying a parent=s verbal consent
during a telephone contact.
$ An excerpt from the permission form signed by the parent or guardian, or signed
by the interviewer for cases with verbal consent.
$ An Immunization History Questionnaire labeled with sufficient information to
identify the child whose immunization records are requested.
$ An excerpt from an article in the Morbidity and Mortality Weekly Report
(MMWR) containing information on national vaccination rates.
$ A pre-addressed, postage-paid return envelope.
Providers are asked to complete the IHQ, or to attach a copy of the child=s immunization records.
Providers are also given the option to return the forms by mail, or to a toll-free fax number.
Reminder/thank you postcards are mailed two weeks after the initial mailing. The postcards
contain the CDC logo to identify study sponsorship, a Athank-you@ to those who have already
returned the original IHQ, and a brief message about the need for and importance of collecting
these data to measure vaccination coverage among children in the U.S.
Reminder packets containing a second copy of the IHQ are mailed three weeks after the postcard
mailing (five weeks from the initial mailing) to providers who have not yet returned the IHQ
from the first mailing. A one-page letter reiterates the importance of provider participation and
requests return of the completed questionnaire. Seven weeks after the initial mailing, provider
offices that still have not responded to the initial request or subsequent mailed reminders receive
a telephone prompt from an experienced interviewer trained to elicit cooperation and record
medical information. The prompting call is a final attempt to obtain the provider questionnaires.
12
Generally, these prompting calls serve to remind providers to return the completed
questionnaires, and they provide an opportunity to mail or fax new materials to those providers
who request them. In some cases, the questionnaire is completed with the interviewer over the
telephone.
The IHQ is then manually edited. If a provider returned a copy of the child’s medical records,
the information is transcribed onto a new IHQ. Every IHQ is reviewed by a quality control
clerk. The cases are then sent to a vendor for data entry. The forms are keyed twice for
verification. The data from the IHQs are then merged with the NHIS data to create the initial
dataset.
2.3.2 Matching and Reconciliation
In matching and reconciliation, every case with provider data is reviewed and compared with the
corresponding data from the NHIS/IM interview. For cases in which the household and provider
data are discrepant, or where provider data are missing, either the household, the provider, or
both are recontacted by telephone or mail to clarify the discrepant data.
The first step in the matching process is to classify the cases into ten adjudication groups. First,
the cases are separated by whether a shot card was used in the initial household interview. Cases
with shot cards are further divided into five groups, depending on whether there is a discrepancy
between the dates and/or doses of the household and provider reports. Cases in which the
household reported only the number of doses of each vaccine from recall are divided into four
groups. Finally, cases in which multiple providers responded for a child but the provider reports
disagreed form the tenth adjudication group. Table 2.2 defines the adjudication groups and gives
the number of children in each in 1997.
A matching sheet is printed for every case. The matching sheet displays key data items for the
child, and all of the household and provider-reported vaccination data. The matching sheets
from each adjudication group are reviewed for discrepancies. Cases that need reconciliation
because of differences between household and provider reports of the number or dates of specific
vaccinations are assigned problem codes that describe the type of discrepancy. These cases are
sent to a specially trained team of telephone interviewers and supervisors for reconciliation.
Additionally, sample children for whom no providers responded in the original data collection
are sent to reconciliation. (See Figure 2.2 for an illustration of the reconciliation process.)
In reconciliation, the providers are called, and interviewers attempt to resolve the discrepancy.
The providers are asked to check their medical records to verify the information returned on the
IHQ or reported by the household. Providers are also asked whether they know of any other
vaccination providers for the child.
13
Table 2.2: Distribution of Cases with Provider Data by Adjudication Group before Reconciliation, 1997
NHIS/NIPRCS
1
Adjudication
Group
Description
Total Number
of Cases
Cases
Requiring
Reconciliation
Household reports from shot record
R1
All dates and numbers of doses matched provider reports
95
0
R2
All numbers of doses matched provider reports, but at least one date
was discrepant
70
4
R3
At least one discrepancy in number of doses; all discrepancies
involved a household over-report
93
92
R4
At least one discrepancy in number of doses; all discrepancies
involved a household under-report
156
17
R5
At least two discrepancies in number of doses; at least one over-
report and one under-report
56
53
Household reports from memory (recall)
H1
No discrepancies in number of doses (including cases where the
household responded “Don=t Know@)
98
10
H2
At least one discrepancy in number of doses; all discrepancies
involved a household over-report
140
108
H3
At least one discrepancy in number of doses; all discrepancies
involved a household under-report
194
13
H4
At least two discrepancies in number of doses; at least one over-
report and one under-report
89
68
Multiple providers
M
Non-identical reports from two or more providers
91
24
Total number of children with provider data
1,082
2
389
1
The distribution of adjudication groups in this table is different than the values of the variable ADJ_GRP in the final data file. This
table shows the number of cases in each group before reconciliation. A case may have a different adjudication group after reconciliation is
completed. For example, the final data file contains 103 cases with ADJ_GRP = H1, as some cases had their discrepancies resolved.
2
The number of children with provider data in reconciliation is higher than the number of children with provider data in the data file.
After reconciliation is completed, the data are reviewed again, and it may be determined that the provider data received for some children are not
valid. Those provider data are then excluded from the file.
14
If the provider is unable to reconcile the discrepancy or cannot be reached, or if the problem
appears to be in the household data, telephone interviewers attempt to contact the household to
resolve the discrepancy. When contacted, the original household respondent or another
knowledgeable adult is asked whether a shot card is available for the child. If the household has a
shot card, specific dates are verified. If no shot card is available, the household respondent is
asked to verify that the child had received vaccinations.
For those cases in which none of the providers for a child responded with vaccination data, a
telephone interviewer contacts the household, verifies the names and addresses of providers
previously reported, and asks for any other providers who may have immunization information
for the child. This group includes cases in which:
$ The provider reported never treating the child.
$ The provider reported treating the child but not having immunization records, or
indicated that the immunization records had been forwarded to another provider.
$ No provider responded for the child.
$ The provider contact information originally reported by the household was
inadequate.
$ An original provider responded with some vaccination information, but it
appeared that the child may have had another vaccination provider.
These households are mailed an advance letter that includes a provider information form and a
consent form that the respondent can return by mail. Ten days after the advance letter is mailed,
telephone interviewers attempt to contact the household by phone. The interviewer confirms the
provider information originally reported by the respondent, and probes the respondent for
additional providers. The interviewer obtains verbal consent to recontact the original providers
and to contact any additional providers. In 1997, 24 cases in which the original provider never
responded were eligible for reconciliation.
15
Figure 2.2: Flow Diagram of 1997 NHIS/NIPRCS Reconciliation Process
Matching identifies
cases for reconciliation
Discrepant data:
needs provider contact
Missing provider data:
contact household for
additional information
Discrepant data:
needs household
contact
Updates to provider
data
Renew permission to
contact providers
Mailout to new
providers and orginal
nonresponding
providers
Contact provider
Resolved?
YES
Contact household
Resolved?
NO
YES
NO
16
Of the 413 total cases eligible for reconciliation, the provider gave new information to reconcile
a discrepancy in 60 cases. In 3 cases, the household reconciled a discrepancy, and in 37 cases
both the household and provider were contacted and the discrepancies were resolved.
Additionally, providers returned data for 20 children for whom provider data were not returned
in the original data collection. These additional data were added to the original provider data for
estimation. Table 2.3 summarizes the impact reconciliation had on the numbers of vaccinations
reported.
Table 2.3: Reconciliation for 1997 NHIS/NIPRCS
Total number of children in reconciliation
413
Number of children with changes to provider-reported number of doses
DTP
Polio
MCV
Hib
Hep B
Varicella
48
46
44
45
59
19
Number of children aged 19-35 months who were not 4:3:1:3 up-to-date
Before reconciliation
After reconciliation
Change in 4:3:1:3 up-to-date status
241
217
-24
Number of children with changes to shot dates
Changes to household-reported shot dates
Changes to provider-reported shot dates
29
68
2.4 Data Processing
After reconciliation is completed, the new data are combined with the original data for the
estimation of vaccination coverage rates. The combined data are reviewed for certain kinds of
discrepancies that may remain, including vaccination dates before the date of birth, consecutive
vaccination dates within 28 days, measles-containing vaccines for children less than 9 months of
age, and vaccination dates that are out of sequence. If the discrepancy can be resolved by
reviewing the dates of other vaccinations the child had received (e.g., it may be evident that part
of the date was transposed or incorrectly written), the data are then edited.
Once all the data have been edited, a disposition code (DISPCODE) that indicates the
completeness and validity of the immunization data is assigned to every case with provider data.
Cases with DISPCODE equal to 7 have provider data, but the completeness of the provider data
is unknown. Therefore, cases with DISPCODE = 7 are not used in calculating the estimates of
vaccination coverage. All other cases with a nonmissing DISPCODE are considered to have
usable provider data.
17
2.5 Informed Consent, Security, and Confidentiality of Information
The data collection procedures of the NHIS assure the respondent of the confidentiality of his/her
responses and the voluntary nature of the survey. Informed consent is obtained from the
respondent (generally the parent or guardian of the child) to participate in the household
interview and also (at the end of the interview) to contact the child's vaccination providers.
Information in the NHIS/NIPRCS is collected and processed under high security. To ensure
privacy of the respondents and confidentiality of sensitive information, NCHS has established
standards for release of data from all NCHS surveys. All CDC staff and contractor staff
involved with the NHIS/NIPRCS sign the NCHS confidentiality agreement and follow
procedures to prevent disclosure.
All information in the NHIS/NIPRCS is collected under strict confidentiality and can be used
only for research purposes [Section 308(d) of the Public Health Service Act, 42 U.S. Code
242m(d), and the Privacy Act of 1974 (5 U.S. Code 552a)]. Prior to the public release, the
contents of the public-use data file go through an extensive review by the NCHS Disclosure
Review Board to protect confidentiality of the participants as well as the data.
18
Chapter 3. Estimation of Vaccination Coverage
3.1 NHIS Weighting Information
The NHIS uses a multistage sample design to represent the civilian noninstitutionalized
population of the U.S.; each person interviewed has a known probability of selection. The
resulting sampling weights (initially equal to the reciprocal of the selection probability) are
adjusted for unit nonresponse and poststratified to population control totals from the Census by
sex, age, and race/ethnicity. Thus, each respondent has a sample weight that can be used to
produce national estimates.
The foundation for the 1997 NHIS/NIPRCS sampling weight is a child-level weight that comes
from the NHIS Immunization Supplement file. This Final Annual Weight (WTFA_IM) is
included in the public-use data file. It includes design, nonresponse, and poststratification
adjustments for sample children under 18 years of age, and additional children aged 12-18
months (quarters 3 and 4) and 19-35 months (quarters 1 to 4) in sampled households.
When including the children between 12 and 18 months in an analysis, this NHIS/IM sampling
weight should be doubled to account for the fact that data were collected in that age group for
only half of the year. (See Section 3.6.)
3.2 Provider-Adjusted Estimates
The provider-adjusted method of estimation produces estimates of percentages of children who
are up-to-date for various vaccines and combinations of vaccines. The provider-adjusted
estimates are calculated by first dividing the children into a set of weighting classes for each
vaccine. Within each weighting class, the proportion of children with usable provider data who
are up-to-date is calculated, and then applied to the total number of children within the weighting
class. These totals are then summed to produce an overall coverage estimate for that vaccine.
These estimates are comparable to the estimates produced in the National Immunization Survey
(Stokley et al. 2000; Bartlett et al. 2001). Section 4.1 gives detailed instructions for calculating
provider-adjusted estimates.
3.3 Adjustment for Effect of Nonresponse Follow-Up Survey
The 1995 NHIS/NIPRCS and 1996 NHIS/NIPRCS included a nonresponse follow-up survey
(NRFUS) of households with children aged 12-35 months who had completed the NHIS/IM
interview but who:
• had not given permission to contact the immunization providers,
• had not supplied adequate information to contact the providers, or
• had reported that their child had never been vaccinated.
19
The NRFUS recontacted these households and asked them again for permission to contact the
immunization providers. If the household gave permission, the immunization data were
collected from the providers using the same procedures as the original data collection. These
new data were combined with the original provider data to calculate estimates of vaccination
coverage. (Westat, Inc. 1999).
The 1997 NHIS/NIPRCS did not conduct a NRFUS. In order to make the estimates comparable
to previous years, adjustment factors were calculated from the results of the 1996 NRFUS. The
adjustment factor for each vaccine or series was determined by dividing the provider-adjusted
estimate of coverage including the NRFUS data by the provider-adjusted estimate calculated
from only the original data collection. For every vaccine and series except Hib, the addition of
the NRFUS data produced a lower estimate of the number of children that were up-to-date.
Therefore, the adjustment factors (shown in Table 3.1) are less than 1 for all vaccines except
Hib.
Table 3.1: Adjustment Factors Based on 1996 NRFUS Data
Vaccine or Series
Adjustment Ratio
DTP
0.9903
DTP3
0.9782
Polio
0.9892
MCV
0.9848
Hib
1.0143
Hep B
0.9926
4:3:1
0.9852
4:3:1:3
0.9799
4:3:1:3:3
0.9776
3.4 Best Values
The best values combine the household and provider data to produce a vaccination report judged
to be the most accurate for each child. Because the best value vaccination dates include data
from both sources, more children have best values for vaccination dates than have provider data.
The inclusion of more children reduces the potential bias in estimates calculated using the best
values for vaccination dates.
20
For the 1997 NHIS/NIPRCS, best values for vaccination dates were developed for two main
groups of children: children with no provider data who were 4:3:1:3 up-to-date according to the
household report from a shot card; and all children who had usable provider-reported vaccination
information.
For the children who were 4:3:1:3 up-to-date from a shot card, the household-reported
vaccination dates were evaluated to see whether they were consistent with the date of birth and
the vaccination schedule. The record was also checked for the degree of agreement between
vaccination dates. If the record met these criteria, then the shot card dates were inserted as best
values for vaccination dates, along with any edits to the dates that seemed warranted, such as
transposed dates or reports with the same month and day but in which the year was inconsistent.
For the children with usable provider data, the household and provider reports were compared.
If the household used a shot card and there was no agreement between the two sources, the
household-reported vaccination dates were considered unusable, and the provider vaccination
dates were used as the best values. (Provider reports that appeared to be inadequate or for the
wrong child were previously excluded. See Section 2.4 for the definition of usable provider
data.) If there was some agreement between the provider-reported and household-reported
vaccination dates, the household information was deemed usable, and these shot card vaccination
dates were used to supplement the provider vaccination dates to create a composite vaccination
record. If the household reported from recall, the provider-reported dates were used as the best
values. Children with best value vaccination dates were assigned a flag (BESTVAL=1) so that
they can easily be identified in the data file.
3.5 Best Value Weights
The sample weights of children with best values for vaccination dates were adjusted to account
for children without best values. The method used to adjust the weights was similar to the
method used in the 1996 NHIS/NIPRCS, in order to maintain comparability among the years. A
total of 11 weighting classes were formed using the following variables: the vaccination status
according to the household report (up-to-date, not up-to-date, missing), shot card use (shot card
used, no shot card), and education of the respondent (high school or less, college or higher,
missing). These three variables resulted in 18 cells; some cells were collapsed when they
contained too few cases. Table 3.2 shows the 11 cells used in the weighting.
21
Table 3.2: Weighting Classes for Adjusting the Weights of Children with Best Values,
1997 NHIS/NIPRCS
Shot card
No Shot card
4:3:1:3 status
according to
household
High school or
less, or missing
College or
higher
High school
or less
Education
missing
College or
higher
Up-to-date
1
2
3
5
4
Not up-to-date
8
9
Missing
6 7
10
11
The sample weight for the children with best values was adjusted by multiplying the NHIS/IM
weight for the child (WTFA_IM) by the ratio of the sum of the weights for all children in the
weighting class to the sum of the weights for children with best values. In addition to this
adjustment, the weights were adjusted through raking (Lohr 1999; Izrael et al. 2000) so that the
sum of the weights agreed with the population control totals for poverty status, race/ethnicity,
and telephone status in the U.S. (This adjustment was not done in 1996.) The result of the
raking is the best value weight (WT_BV2).
Some of the best value weights, specifically those of children 12-18 months, are high. This
occurred because not all children between 12 and 18 months in the NHIS/IM were in the
NHIS/NIPRCS sample, and some children with best values were in weighting classes that had a
large number of children without best values. In other words, these children had characteristics
more associated with children without best values. (See Appendix H for summary statistics of
the NHIS/IM weights and the best value weights.)
3.6 Imputed Best Values
For children without best values, imputation was used to calculate a total number of doses for
each antigen and the up-to-date status of the child. The variables considered for forming
imputation classes were the same as those used to form the weighting classes for children with
best values: whether a child was up-to-date on the 4:3:1:3 series according to the household
report, whether a shot card was used, and the education of the respondent. Some of the 18 cells
in the cross-classification of the three variables were collapsed after looking at the distribution of
children in the sample. Cells that contained few donors relative to the recipients were collapsed,
resulting in a total of seven imputation classes.
22
Table 3.3: Imputation Classes for Imputing Missing Best Values,
1997 NHIS/NIPRCS
Shot card
No shot card
4:3:1:3 status
according to
household
High school or
less, or missing
College or
higher
High school or
less, or missing
College or
higher
Up-to-date
1
2
3
Not up-to-date
6
Missing
4
5
7
Within each imputation class, a hot-deck imputation procedure was used to impute the number of
doses of each vaccine and series using data from children with non-missing best values. Cases in
which best values were imputed are marked by the variable IMP_FLAG.
3.7 Children Aged 12-18 Months
The 1997 NHIS/IM collected data for children between 12 and 18 months only for the last two
quarters of the year. To estimate the total number of children receiving various numbers of
doses of specific vaccines during an entire year, the NHIS sampling weights for children 12 to 18
months were doubled prior to any other adjustments for missing data. A total of 462 children
were sampled in this age group.
In the absence of a standard definition of Aup-to-date@ for children between 12 and 18 months of
age for either a specific vaccine or a series of vaccines, the best values were used to calculate
weighted percentages of children receiving one or more doses of each vaccine. (See Appendix C
for a table with these estimates.)
23
Chapter 4. Calculating Estimates of Vaccination
Coverage and Standard Errors
As mentioned in the previous chapter, the NHIS/NIPRCS uses several methods for producing
estimates of vaccination coverage. This chapter provides the user of the data set with
instructions for replicating these methods.
4.1 Provider-Adjusted Estimates of Vaccination Coverage
As described in Section 3.2, the provider-adjusted estimates use the children with usable
provider data to estimate the proportion of children who are up-to-date in the sample as a whole.
The steps required to obtain the estimates are given below:
Step 1: Use the sample weight WTFA_IM in the following steps.
Step 2: All children between the ages of 19 and 35 months for whom the NHIS/IM was
completed are divided into weighting classes specific to each vaccine. The weighting
classes form two main groups according to whether the household used a shot card. All
children belonging to households that used shot cards to report the number and dates of
vaccinations are in the first group, and children from households that reported from
memory recall belong to the second group. Within each main group, children are divided
into subgroups by the number of doses reported by the household. Table 4.1 shows the
weighting classes for calculating the provider-adjusted estimate of DTP coverage.
The weighting classes for the other vaccines appear in Appendix D in the column
“Number of Doses Reported by Household.”
Step 3: Sum the weights (WTFA_IM) of children with usable provider data in each
weighting class. This gives the estimated number of children with provider data. Call
this Sum 1. (See Column 1 in Table 4.2.)
Next, sum the sample weights of all children with usable provider data who are up-to-
date on the specific vaccine. This gives the estimated number of children who are up-to-
date among children with provider data. Call this Sum 2. (See Column 2 in Table 4.2.)
Compute the ratio [ Sum 2/Sum 1]. This gives the proportion of children with usable
provider data who are up-to-date in this weighting class. (See Column 3 in Table 4.2.)
24
Table 4.1: Weighting Classes for DTP, 1997 NHIS/NIPRCS
Use of Shot Card
Number of Doses of DTP
Shot Card Used
4+
3
2
1
0
No Shot Card
4+
3
2
1
0
All*
Don=t know/Missing
*The household respondent was not able to give the total number of shots received,
but indicated that the child was up-to-date on this vaccine.
Step 4: Apply this proportion to the total weighted number of children in the weighting
class. The total weighted number of children is obtained by simply aggregating the
sample weights of all children. (See Column 4 in Table 4.2) This product gives the
estimated number of children who are up-to-date in that weighting class. (See Column 5
in Table 4.2)
Step 5: Aggregate the estimated numbers of children who are up-to-date on the specific
vaccine over all weighting classes. (See the Total entry in Column 5 in Table 4.2.)
Step 6: Divide the number obtained in Step 5 by the total estimated number of children
over all the weighting classes. This is simply the sum of the weights of all children who
completed the NHIS/IM. (See the Total entry in Column 4 in Table 4.2.)
Step 7: The number obtained in Step 6 (when multiplied by 100) gives the percentage
of children who are up-to-date on the specific vaccine. This is the provider-adjusted
estimate of coverage for that vaccine.
25
Table 4.2: Calculation of Provider-Adjusted Estimate for DTP, 1997 NHIS/NIPRCS
Weighting
Class
(1)
Sum of the
weights of all
children with
usable
provider data
(2)
Sum of the
weights of
children who
are up-to-date
among
children in (1)
(3)=(2)/(1)
Proportion
of children
who are up-
to-date
(4)
Sum of the
weights of all
children with
and without
provider data
(5)=(4)x(3)
Estimated
number of
children who
are up-to-date
Shot Card 4+
794,766
742,740
0.935
1,389,989
1,298,999
3
222,992
130,059
0.583
397,572
231,882
2
34,599
25,797
0.746
71,939
53,638
1
11,364
8,122
0.715
32,925
23,532
0
916
916
1.000
9,282
9,282
No Shot Card 4+
103,181
80,636
0.782
215,768
168,623
3
83,782
65,107
0.777
190,017
147,662
2
38,331
30,126
0.786
85,568
67,252
1
9,816
4,285
0.437
37,422
16,336
0
11,580
11,580
1.000
108,912
108,912
All*
814,820
704,768
0.865
2,323,786
2,009,929
Don=t Know/
Missing
199,179
155,248
0.779
747,598
582,707
Total
2,325,326
1,959,384
5,610,778
4,718,754
Percentage of children who are up-to-date for DTP = [ 4,718,754/5,610,774] x 100 =
84.1%
*The household respondent was not able to give the total number of shots received, but reported that the child
was up-to-date on this vaccine.
See Appendix A for the provider-adjusted estimates of coverage for other vaccines and series.
The provider data in the data file include the results from reconciliation, so estimates calculated
using the provider-adjusted method will correspond to the column labeled “Initial +
Reconciliation” in the table in the appendix.
4.2 Including the Nonresponse Follow-Up Survey Adjustment in
Coverage Estimates
Both provider-adjusted estimates and best value estimates (discussed below) for individual
vaccine coverage should be multiplied by the NRFUS adjustment factor in Table 3.1. For
example, the provider-adjusted estimate of DTP coverage calculated in Table 4.2 (84.1%)
26
should be multiplied by the adjustment factor (0.9903) to obtain a final NRFUS-adjusted
coverage estimate of 83.3%. (See Appendix A for the estimates of vaccination coverage that
include the NRFUS adjustment.)
When calculating coverage estimates for the entire sample or any subgroup, these NRFUS
adjustment factors should be applied.
4.3 Best Value Estimates and Using Imputed Best Values
Best value estimates should be calculated using the best value weight (WT_BV2), which
incorporates an adjustment for children without best values. The results should then be
multiplied by the NRFUS adjustment to derive the Final Best Value estimates.
When using the imputed best values, the NHIS/IM sampling weight (WTFA_IM) should be
used. Cases for which best values were imputed are flagged in the data set (IMP_FLAG = 1).
See Appendix A for the coverage estimates for each vaccine and series using the best value and
imputed best value data.
4.4 Calculating Standard Errors
4.4.1 Standard Errors of NHIS Estimates
Data users should refer to the report Design and Estimation for the 1995-2004 National Health
Interview Survey (Series 2, No. 130), available on the NCHS Web site
http://www.cdc.gov/nchs/nhis.htm , for detailed instructions on how to calculate standard errors
(using SUDAAN) for the 1997 NHIS estimates.
4.4.2 Standard Errors of Best Value Estimates
Vaccination coverage rates are ratio estimates, and the Taylor linearization method can be used
to compute the standard errors of these estimates (Nixon et al. 1996). For computing the
standard errors of best value estimates of vaccination coverage rates, the “pseudostrata” created
for the NHIS with two PSUs per stratum were first considered. Because only a subset of the
sample of children had best values, many of the strata were empty, in the sense that the two
PSUs in the stratum did not have children with best values. Therefore, the 337 NHIS strata
were collapsed to 185 strata such that each stratum had two PSUs containing children with best
values. The standard errors of the best value estimates were computed using SUDAAN software
(Shah et al. 1997). Appendix E gives an example of a SAS program that calls SUDAAN
program that was used to calculate standard errors, including the specifications for collapsing
the 1997 NHIS strata. Other software such as STATA (Stata Corporation 2001) or SAS (SAS
Institute Inc. 1999) can also be used to estimate the standard errors by the Taylor linearization
method.
27
The standard errors of the best value estimates for all vaccines and series can be found in
Appendix A.
4.4.3 Standard Errors of Estimates Based on Imputed Best Values
Treating the imputed best values as if they were responses and then computing the variance
estimates, using a standard method like Taylor linearization, generally results in
underestimation of the variance. Alternative methods of variance estimation take into account
the presence of imputed values and adjust for this underestimation. A jackknife variance
estimation method suggested by Rao and Shao (1992) was used to compute the variance of the
estimates based on imputed values. (For details of this procedure, see the internal methodology
report. Abt Associates Inc. 2002.) The Table in Appendix A includes these standard errors.
28
Chapter 5. Public-Use Data File
This chapter contains details about the 1997 NHIS/NIPRCS data file and information for users
and analysts of these data. The data file is in ASCII format. A code book and a program for
reading the data into SAS are available with this data file.
5.1 File Description
Data in the PUF come from two sources: the 1997 NHIS/IM and the 1997 NHIS/NIPRCS. The
source of each variable is noted in the code book. Data are provided at the child level; that is,
each child has one record, which includes the household and provider information. The data
file contains 2,622 records for children aged 12-35 months. If more than one child was
interviewed in a household, the household variables, including the ID number, are included in
each child=s record.
5.2 Data Cleaning
Data from the Immunization History Questionnaire (IHQ) were checked for internal
consistency, including skip-pattern logic and out-of-range or otherwise invalid values. The
provider data file was checked for duplicate records from the same provider. When a child had
data from more than one IHQ, decision rules were applied to produce the most complete record
of the child=s immunization history. The analyst should refer to the documentation provided by
the NCHS for data collected in the NHIS or the NHIS/IM.
As described in Sections 2.3.2 and 2.4, some provider data may have been edited as a result of
the reconciliation and file preparation processes.
For shot date variables from the IHQ, if the day of the month was missing, it was imputed to
“15” for the purpose of calculating the age in days at the time of vaccination. If this value
created a vaccination date before the child=s date of birth, the value would be changed to be
equal to the date of birth.
29
5.3 Missing Value Codes
A standard coding scheme, based on the NHIS protocol designates Arefused@ and Adon=t know@
responses on all variables. ARefused@ responses are coded as A7@ (with leading 9s filling the
width of the field), and Adon=t know@ responses are coded as A9@ (again, with leading 9s). A
code of A8@ indicates Anot ascertained@ responses, which typically occur when an in-the-universe
respondent had a blank field or the field contained an invalid code.
Because the appropriateness of some questions depended on the availability of shot records, not
all questions were asked of all respondents. Cases that were not eligible to answer specific
questions are coded as A. <BLANK: NOT IN UNIVERSE>.” The notes in the code book
describe the universe for each question.
5.4 Variable Naming Conventions
The provider data from the Immunization History Questionnaires are used to create numerous
child-level composite variables, as described below. The names of the variables giving the
number of doses received for each vaccine begin with P_NUM. For example, P_NUMHEP
gives the number of doses of hepatitis B vaccine received by the child according to the provider
data.
The provider data are also used to form variables for age in days and age in months at each
vaccination. For age in days and age in months, either 4 or 8 variables are created, depending on
the number of doses recommended for the vaccine. The variable names for age in months end
with AGn, where n is the dose number. For example, HEPAG1 to HEPAG8 give age in months
for 8 possible doses of hepatitis B vaccine. Similarly, for age in days at vaccination, the variable
names start with D and end with AGn. DHEPAG1 to DHEPAG8 give age in days for 8 possible
hepatitis B vaccination doses.
An up-to-date status indicator variable was created for each vaccine. These variables use the
best values. Each of these variables begins with B_UTD. For example, the variable B_UTDHEP
indicates whether the child received 3 or more doses of hepatitis B vaccine.
To accommodate the large number of types of vaccinations, a vaccination-type variable was
created for each shot or dose. For example, the vaccination-type variable for DTP indicates
whether the specific dose was a DTP, DTaP, DT, unknown (unmarked) type of DTP, DTP-Hib,
DTaP-Hib, or an unknown (unmarked) type of DTP-Hib vaccination.
30
5.5 Explanatory Notes for Specific Variables
Variable name: ADJ_GRP
The adjudication groups are used for assessing agreement and consistency between the
provider report(s) and the household report of vaccinations. See Section 2.3.2 for a more
detailed explanation of the matching and reconciliation procedures.
Household reports from shot record
R1 All dates and numbers of doses match provider reports
R2 All numbers of doses match provider reports, but at least one date is discrepant
R3 At least one discrepancy in number of doses; all discrepancies involve a
household over-report
R4 At least one discrepancy in number of doses; all discrepancies involve a
household under-report
R5 At least two discrepancies in number of doses; at least one over-report and one
under-report
Household reports from memory recall
H1 No discrepancies in number of doses (includes cases where the household
responds ADon=t Know@)
H2 At least one discrepancy in number of doses; all discrepancies involve a
household over-report
H3 At least one discrepancy in number of doses; all discrepancies involve a
household under-report
H4 At least two discrepancies in number of doses; at least one over-report and one
under-report
Multiple provider reports
M Non-identical reports from two or more providers
Variable name: DISPCODE
The DISPCODE refers to the completeness and validity of the immunization information
from all the Immunization History Questionnaires returned for the child.
1 All identified providers responded, no problems indicated in cross-check
between household and provider shot dates.
2 All identified providers responded, no shot card to cross-check.
3 All identified providers responded, poor immunization history matching
results.
4 All identified providers responded, poor immunization history matching
results, additional mismatch indicators present.
5 Some but not all identified providers responded, but provider information
indicates 4:3:1:3:3 up-to-date.
6 Some but not all identified providers responded, but provider information
31
matches shot card immunization history.
7 Some but not all identified providers responded, completeness of provider
immunization history is unknown.
8 Some but not all identified providers responded, but provider information
indicates 4:3:1:3:3 up-to-date when immunizations after the interview date
are included.
9 Some but not all identified providers responded, but provider information
indicates at least as many doses for each vaccine as the household respondent
(or at least 1 dose for MCV).
10 Some but not all identified providers responded, but the household reported
an inexact number of vaccinations (AAll,@ ADon=t Know,@ ARefused@ or
missing) for one or more vaccines, and any exact responses meet previous
criteria (for DISPCODE 9).
11 Some but not all identified providers responded, but definite number of shots
was reported by household not from a shot card for one or more vaccines,
and any other vaccines meet previous criteria (for DISPCODE 9 or 10).
When analyzing children with provider data, cases with DISPCODE = 7 should not be
included.
Variable names: NUM_DTP, NUM_POLI, NUM_MMR, NUM_HIB, NUM_HEPB,
NUM_CPOX
These variables were calculated by totaling the number of each type of vaccination reported
by the household respondent in the NHIS/IM, either from a shot card or from recall.
Variable name: PSU
The variable identifies the primary sampling unit (PSU) and is used in variance estimation.
Refer to the NHIS/IM documentation for more information.
Variable name: STRATUM
To calculate the standard errors of the best value estimates of vaccination coverage, the
original NHIS strata need to be collapsed. See Appendix E for an example program.
Variable name: WTFA_IM
For children aged 12-18 months, this weight should be doubled for estimation.
32
5.6 Flags
The following flag variables are included in the data file:
BDOBFLAG A value of 1 indicates that no provider date of birth information was obtained
and BEST_DOB is the date of birth reported by the household respondent.
BESTVAL A value of 1 indicates that best values for vaccination dates were determined. A
value of 2 indicates that the child does not have best values.
BRDOBFLG A value of 1 indicates that BEST_DOB was assigned after recontacting the
household and/or providers to reconcile differences.
IMP_FLAG A value of 1 indicates that best value vaccination status was imputed.
PRO_FLAG A value of 1 indicates that the child was 4:3:1:3 up-to-date according to the
household=s shot record. A value of 2 indicates the child was not 4:3:1:3 up-to-
date. The value is missing for children in households that did not use shot cards.
5.7 Data Alerts
This section details known problems with the data.
Considerable time elapsed between the 1997 NHIS/IM data collection and the collection of
vaccination data from providers, in some cases up to three years. The consent given by
respondents was good for one year only, and in many cases it was necessary to renew the
permission form before sending the Immunization History Questionnaire to providers. In total,
1,212 valid permission forms with complete provider information were collected by the Census
Bureau. Of those, 160 cases expired before a questionnaire could be mailed to the provider.
Eighty-nine of those cases had permission renewed. Between the number of valid forms
collected, the forms that expired, and provider nonresponse a relatively low percentage of
children ended up with provider vaccination data.
Although all provider-reported shot dates are reviewed and sent for reconciliation, some
inconsistencies may remain in the data that could not be verified. These include shot dates that
are too close together, and certain shots given before 38 days of age that are not recommended.
Further, any variables derived from the provider reports (e.g., VISITS) may contain
inaccuracies if those data could not be reconciled or verified.
33
5.8 Code Book
A complete listing of the variables included in the public-use data file is available in the 1997
National Health Interview Survey/National Immunization Provider Record Check Study Public-
use Data File Code Book. The code book contains a table of contents and an alphabetic list of
variables. Then each variable is listed with either 1) the frequency of a given response, the
response value, and the formatted response label; 2) a count of missing and non-missing values
with summary statistics; or 3) a count of missing/non-missing values.
For categorical variables, the code book gives the frequency of each category. For continuous
variables, the mean, median, minimum, and maximum values are displayed.
5.9 Guidelines for Citation of Data
Any published material derived from the data should acknowledge NCHS as the original source.
The suggested citation to appear at the bottom of all tables is as follows:
Source: CDC, NIP and NCHS (2002), 1997 National Health Interview
Survey/National Immunization Provider Record Check Study
In a bibliography, the citation should read:
U.S. Department of Health and Human Services. 1997 National Health Interview
Survey/National Immunization Provider Record Check Study (machine readable data
file and documentation). National Center for Health Statistics, Centers for Disease
Control and Prevention, Hyattsville, MD, 2002.
The published material should also include a disclaimer that credits any analyses,
interpretations, or conclusions reached to the author (recipient of the data file) and not to
NCHS, which is responsible only for the initial data. Consumers who wish to publish a
technical description of the data should make an effort to ensure that the description is not
inconsistent with that published by the NCHS.
Please place the acronym NHIS/NIPRCS in the titles, keywords, or abstracts of journal articles
and other publications in order to facilitate retrieval of such materials in bibliographic searches.
References
Abt Associates Inc. 2002. NHIS/NIPRCS 1997 Final Methodology Report. Submitted to the
National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville,
MD. Chicago, IL: Abt Associates Inc.
Bartlett, Diana L., Ezzati-Rice, Trena M., Stokley, Shannon, and Zhao, Zhen. 2001. Comparison
of NIS and NHIS/NIPRCS Vaccination Coverage Estimates. American Journal of Preventive
Medicine, Volume 20, Number 4S, pp. 25-27.
Ezzati-Rice, Trena M., Zell, Elizabeth R., Massey, James T., and Nixon, Mary Gessley. 1996.
Improving the Assessment of Vaccination Coverage Rates with the Use of Both Household and
Medical Provider Data. 1996 Proceedings of the Section on Survey Research Methods,
Alexandria, VA: American Statistical Association, pp. 335-340.
Izrael, David, Hoaglin, David C. and Battaglia, Michael P. 2000. A SAS Macro for Balancing a
Weighted Sample. The Twenty-Fifth Annual SAS User’s Group International Conference,
Cary, NC: SAS Institute, Inc. pp. 1350-1355.
Lohr, Sharon L. 1999. Sampling: Design and Analysis. Pacific Grove, CA: Duxbury Press.
Nixon, Mary Gessley, Kalton, Graham, Brick, J. Michael, Ezzati-Rice, Trena, Zell, Elizabeth R.
1996. Variance Estimation with Missing Best Values in the NIPRCS. 1996 Proceedings of the
Section on Survey Research Methods, Alexandria, VA: American Statistical Association, pp.
347-352.
Peak, Rebecca R. and Cadell, Diane M. 1996. Overview of the National Immunization Provider
Record Check Study. 1996 Proceedings of the Section on Survey Research Methods,
Alexandria, VA: American Statistical Association, pp. 332-334.
Rao, J.N.K., and Shao, J. 1992. Jackknife Variance Estimation with Survey Data under Hot
Deck Imputation. Biometrika, 79, pp. 811-822.
SAS Institute Inc. 1999. SAS/STAT User’s Guide Version 8. Cary, NC: SAS Institute Inc.
Shah, B.V., Barnwell, B.G. and Bieler, G.S. 1997. SUDAAN User’s Manual, Release 7.5.
Research Triangle Park, NC: Research Triangle Institute.
Stata Corporation. 2001. Stata Reference Manual. College Station, TX: Stata Press.
34
Stokley, Shannon, Battaglia, Michael P., Khare, Meena, Daniels, Danni, and Ezzati-Rice, Trena
M. 2000. Comparison of the NIS and NHIS/NIPRCS Estimation Methods. 2000 Proceedings of
the Section on Survey Research Methods, Alexandria, VA: American Statistical Association, pp.
721-725.
Westat, Inc. 1999. 1996 National Immunization Record Check Study (NIPRCS) Final Methods
Report. Submitted to the National Center for Health Statistics, Centers for Disease Control and
Prevention, Hyattsville, MD.
Zell, Elizabeth R., Ezzati-Rice, Trena M., Massey, James T., and Brick, J. Michael. 1996.
Response Errors Associated with Household Reports of Immunizations: Analysis of Subgroup
Differences. 1996 Proceedings of the Section on Survey Research Methods, Alexandria, VA:
American Statistical Association, pp. 341-346.
35
APPENDICES
Estimates of Vaccination Coverage among Children Aged 19-35 Months in the 1997 NHIS/NIPRCS
Provider-Adjusted Estimates Best Value Estimates and Standard Errors
Vaccination
or Series
1
Initial
Estimate
2
Initial +
Reconciliation
Final
Provider-
Adjusted
3
Before NRFUS
Adjustment
4
Final Best Values
5
Including Imputed Best Values
6
Estimate S.E Estimate Rao-Shao S.E.
7
DTP 83.7 84.1 83.3 83.5 82.7 1.4 84.0 1.3
DTP3 95.4 95.4 93.3 95.5 93.4 0.9 95.3 0.8
POLIO 90.9 91.7 90.7 91.3 90.3 1.1 91.6 1.0
MCV 91.6 92.4 91.0 92.5 91.1 1.0 92.8 0.9
HIB 93.1 93.3 94.6 93.2 94.5 1.2 93.3 1.0
HEPB 84.2 86.0 85.4 85.9 85.3 1.2 86.5 1.4
4:3:1 80.5 82.1 80.9 82.2 81.0 1.3 82.8 1.3
4:3:1:3 79.5 81.2 79.6 81.3 79.7 1.4 81.9 1.3
4:3:1:3:3 72.3 75.4 73.7 74.9 73.2 1.4 75.8 1.4
1 4:3:1 means up-to-date with 4 or more doses of DTP, 3 or more doses of polio and 1 or more doses of MCV. 4:3:1:3 includes 3 or more doses of Hib 4:3:1:3:3 includes 3 or more doses of Hep B.
2 Provider-adjusted estimates are calculated from provider-reported data. See Section 4.1 for a complete description of how provider-adjusted estimates are calculated. The initial estimate is
calculated from unreconciled data and cannot be reproduced using the public-use file.
3 The provider-adjusted estimates, including reconciliation, are multiplied by a ratio calculated from the 1996 NRFUS. See Section 3.3 for a description of the NRFUS adjustment procedures.
4 Best value estimates are calculated for all children with best vaccination values. The weight used to calculate these estimates is WT_BV2. See Section 3.4 for a description of the best value
procedures.
5 The Final Best Value estimates include the NRFUS adjustment. See Section 4.4 for a description of the standard errors.
6 The up-to-date status is imputed for children who do not have best value vaccination values. See Section 3.6 for a description of the imputation process.
7 See Section 4.4 for a description of variance estimation for imputed values.
NATIONAL IMMUNIZATION PROVIDER RECORD CHECK STUDY
IMMUNIZATION HISTORY QUESTIONNAIRE
INSTRUCTIONS: Please review your records and complete this questionnaire for the child identified below. Then mail it in the
postage-paid envelope provided or fax it to: FAX: 1-800-293-5155
The Immunization History Questionnaire is voluntary. The National Center for Health Statistics, the Centers for
Disease Control and Prevention, their contractors or grantees will use this information only for statistical purposes
in health research, and no information which identifies the child, the child=s family, doctors or medical care
providers will ever be released or published. (Title 42, United States Code, Section 242k.)
FOR OFFICE USE ONLY
For LABEL placement (printed from NIPTRACK)
TYPE
Telephone
Mail
Fax
1. Which of the following best describes your records of immunization for this child? (Check only one box.)
1 G a. Have immunization record for this child. (Go to item 2 below.)
2 G b. Have provided care to this child, but do not have his/her immunization record. (Go to question 3 on next page.)
3 G c. Have no record of providing care to this child. (Return questionnaire to CDC as instructed above.)
4 G d. Other: _____________________________________________________
2. Referring to all sources of immunization history, please specify below the month, day and year when each of the following
immunizations was given, either by your office or by another provider (OP), as documented in your records. If you prefer, you
may attach a copy of the complete immunization history and complete Questions 3 through 12.
Circle the "OP" for any immunization given by another provider, after the date for that immunization. Please see item 12.
Dates of immunization
(MM
-
DD
-
YYYY)
(1)
(2)
(3)
(4)
(5)
DT/DTP/DTaP
(check one box per date)
- - OP
9 DT 9 DTP
9 DTaP
- - OP
9 DT 9 DTP
9 DTaP
- - OP
9 DT 9 DTP
9 DTaP
- - OP
9 DT 9 DTP
9 DTaP
- - OP
9 DT 9 DTP
9 DTaP
DTP-Hib (Tetramune or
Acthib/DTP)
- - OP
- - OP
- - OP
- - OP
- - OP
Hib
- - OP
- - OP
- - OP
- - OP
- - OP
Hepatitis B
(enter date or check box)
- - OP
9 Administered at birth
- - OP
- - OP
- - OP
- - OP
Polio (OPV or IPV)
(check one box per date)
- - OP
9 OPV 9 IPV
- - OP
9 OPV 9 IPV
- - OP
9 OPV 9 IPV
- - OP
9 OPV 9 IPV
- - OP
9 OPV 9 IPV
MMR
- - OP
- - OP
- - OP
- - OP
- - OP
Measles only
- - OP
- - OP
- - OP
- - OP
- - OP
Varicella
- - OP
- - OP
- - OP
- - OP
- - OP
Other Vaccines (Specify)
- - OP
- - OP
- - OP
- - OP
- - OP
CDC64.137 (5,1999)
3. What was the date of this child's first visit for any reason to this place of practice?
_____ - ______ - _____ or 8 G Don't Know
mm dd yyyy
4. What was the date of this child's most recent visit for any reason to this place of practice?
_____ - ______ - _____ or 8 G Don't Know
mm dd yyyy
5. Which types of care does this facility routinely provide? (Check all that apply.)
1 G a. Comprehensive well-child care (examination,
anticipatory guidance, screening)
2 G b. Acute illness care
3 G c. Follow-up visits
4 G d. After-hours telephone coverage
5 G e. WIC Program/services
6 G f. Other (Describe:)
6. Which of the following best describes this facility? (Check only one box, representing the most specific description.)
1 G a. Private Practice
2 G b. Public Health Department-operated clinic
3 G c. Hospital Outpatient Clinic
4 G d. Community/Migrant Health Center
5 G e. Military Health Care Facility
6 G f. Other Facility (Describe:)
7. Is this facility a Vaccines for Children provider?
1 G a. Yes 2 G b. No 3 G c. Unknown
8a. Was this facility ever this child=s medical home for primary care? (Medical home: the place where care is delivered or directed
by practitioners known to the child and family, who are able to manage or facilitate essentially all aspects of pediatric care.)
1 G a. Yes (Go to question 2 G b. No (Go to item 9.) 3 G c. Unknown (Go to item 9.)
8b. If Yes, what specialty is (was) this child’s primary care provider?
1 G a. Pediatrician
2 G b. Family Physician
3 G c. General practitioner
4 G d. Other (Describe)______________________________
9. Name of person completing questionnaire: (print)_______________________________________________________
Phone: ( ) Signature:
10. According to your records, what is this child's date of birth? _____-_____-_____ or 8 G Don't know
mm dd yyyy
11. According to your records, did this child ever use another last name (excluding names prior to adoption)?
1 G Yes [Specify name(s):] 2 G No
INSTRUCTIONS: If you know of other providers that may have immunization records for this
child, please continue with item 12. Otherwise, return this questionnaire to CDC. Call 1-877-652-
1244 (toll-free) with any questions. Thank you.
12. Please enter below the names, addresses and telephone numbers of other providers who may have an immunization record for
this child, and the name and address for any provider of immunizations with OP circled in item 2.
(1) (2) ____________________________________
_____________________________________
_____________________________________
( ) ( ) _________________________________
Weighted Best Value Estimates of Vaccination Coverage Among Children Aged 12-18 Months
(n=177) , 1997 NHIS/NIPRCS
Percent of children receiving number of doses of vaccines
None
1
2
3
4+
Vaccine/
Series
Est
(%)
S.E.
Est
(%)
S.E.
Est
(%)
S.E.
Est
(%)
S.E.
Est
(%)
S.E.
Total
DTP
-
-
1.6
1.1
15.9
4.2
54.9
5.1
27.6
1.9
100.0
Polio
-
-
1.6
1.1
33.7
2.3
64.7
2.4
-
-
100.0
MCV
37.3
5.9
62.7
5.9
-
-
-
-
-
-
100.0
Hib
-
-
4.6
1.8
15.3
4.4
80.1
4.6
-
100.0
Hep B
1.2
0.9
2.0
1.1
14.8
3.3
82.0
3.8
-
-
100.0
Note: A dash in the cell means that the sample contained no children in this category.
Provider-adjusted estimates
Children 19-35 months old
Weighted (weight = WTFA_IM)
DTP
Final
Final Provider
Number of Without Total With Provider adjusted
Doses Reported Provider Provider Up_to_ adjusted up-to-
By household Data Data date Percent Total up-to-date date(%)
Shot card, 4+ 595223 794766 742740 93.45 1389989 1298999
3 174580 222992 130059 58.32 397572 231882
2 37340 34599 25797 74.56 71939 53638
0 8366 916 916 100.00 9282 9282
No shot card, 4+ 112587 103181 80636 78.15 215768 168623
3 106235 83782 65107 77.71 190017 147662
2 47237 38331 30126 78.59 85568 67252
1 27606 9816 4285 43.65 37422 16336
0 97332 11580 11580 100.00 108912 108912
All 1508966 814820 704768 86.49 2323786 2009929
DK/Missing 548419 199179 155248 77.94 747598 582707
Total 3285452 2325326 1959384 84.26 5610778 4718754 84.10
Provider-adjusted estimates
Children 19-35 months old
Weighted (weight = WTFA_IM)
DTP3
Final
Final Provider
Number of Without Total With Provider adjusted
Doses Reported Provider Provider Up_to_ adjusted up-to-
By household Data Data date Percent Total up-to-date date(%)
Shot card, 3+ 769803 1017758 987409 97.02 1787561 1734257
2 37340 34599 26585 76.84 71939 55276
1 21561 11364 8122 71.47 32925 23532
0 8366 916 916 100.00 9282 9282
No shot card, 3+ 218822 186963 186963 100.00 405785 405785
2 47237 38331 33241 86.72 85568 74205
1 27606 9816 8335 84.91 37422 31776
0 97332 11580 11580 100.00 108912 108912
All 1508966 814820 777025 95.36 2323786 2215998
DK/Missing 548419 199179 185422 93.09 747598 695963
Total 3285452 2325326 2225598 95.71 5610778 5354986 95.44
Provider-adjusted estimates
Children 19-35 months old
Weighted (weight = WTFA_IM)
POLIO
Final
Final Provider
Number of Without Total With Provider adjusted
Doses Reported Provider Provider Up_to_ adjusted up-to-
By household Data Data date Percent Total up-to-date date(%)
Shot card, 3+ 708689 973887 933540 95.86 1682576 1612869
2 79071 76739 47912 62.44 155810 97280
1 39158 8964 5722 63.83 48122 30718
0 10152 5047 5047 100.00 15199 15199
No shot card, 3+ 203404 150845 132663 87.95 354249 311550
2 78693 48021 39578 82.42 126714 104435
1 28463 30723 25893 84.28 59186 49881
0 100311 7331 7331 100.00 107642 107642
All 1497121 822231 758007 92.19 2319352 2138189
DK/Missing 540390 201538 184440 91.52 741928 678985
Total 3285452 2325326 2140133 92.04 5610778 5146748 91.73
Provider-adjusted estimates
Children 19-35 months old
Weighted (weight = WTFA_IM)
MCV
Final
Final Provider
Number of Without Total With Provider adjusted
Doses Reported Provider Provider Up_to_ adjusted up-to-
By household Data Data date Percent Total up-to-date date(%)
Shot card, 1+ 756567 937965 903909 96.37 1694532 1633006
0 80503 126672 85908 67.82 207175 140505
No shot card, 1+ 298223 205388 190892 92.94 503611 468067
0 207420 63410 49933 78.75 270830 213268
All 1375270 759575 708806 93.32 2134845 1992155
DK/Missing 567469 232316 214346 92.26 799785 737920
Total 3285452 2325326 2153794 92.62 5610778 5184921 92.41
Provider-adjusted estimates
Children 19-35 months old
Weighted (weight = WTFA_IM)
HIB
Final
Final Provider
Number of Without Total With Provider adjusted
Doses Reported Provider Provider Up_to_ adjusted up-to-
By household Data Data date Percent Total up-to-date date(%)
Shot card, 3+ 599554 839522 804598 95.84 1439076 1379211
2 69421 72001 61164 84.95 141422 120136
1 66192 77929 66498 85.33 144121 122981
0 101903 75185 71011 94.45 177088 167257
No shot card, 3+ 139672 101132 101132 100.00 240804 240804
2 57832 30795 28796 93.51 88627 82874
1 45133 40650 36078 88.75 85783 76135
0 240926 91018 82702 90.86 331944 301615
All 1293864 728605 678698 93.15 2022469 1883937
DK/Missing 670955 268489 245952 91.61 939444 860587
Total 3285452 2325326 2176629 93.61 5610778 5235537 93.31
Provider-adjusted estimates
Children 19-35 months old
Weighted (weight = WTFA_IM)
HEP B
Final
Final Provider
Number of Without Total With Provider adjusted
Doses Reported Provider Provider Up_to_ adjusted up-to-
By household Data Data date Percent Total up-to-date date(%)
Shot card, 3+ 631329 860070 816844 94.97 1491399 1416443
2 103532 110323 76726 69.55 213855 148729
1 34596 30353 21939 72.28 64949 46945
0 67613 63891 34876 54.59 131504 71784
No shot card, 3+ 169823 142184 118111 83.07 312007 259181
2 72614 32837 28873 87.93 105451 92721
1 67040 35274 30541 86.58 102314 88586
0 285476 127171 79847 62.79 412647 259089
All 1209764 644909 580303 89.98 1854673 1668875
DK/Missing 643665 278314 232901 83.68 921979 771538
Total 3285452 2325326 2020961 86.91 5610778 4823891 85.98
Provider-adjusted estimates
Children 19-35 months old
Weighted (weight = WTFA_IM)
4:3:1
Final
Final Provider
Number of Without Total With Provider adjusted
Doses Reported Provider Provider Up_to_ adjusted up-to-
By household Data Data date Percent Total up-to-date date(%)
Shot card Up-to-date, Number 549323 744269 689640 92.66 1293592 1198643
not Up-to-date 287747 320368 197172 61.55 608115 374267
No Shot card, Up-to-date ,All 1385374 773804 672259 86.88 2159178 1875833
Up-to-date -Number 77900 71342 56717 79.50 149242 118648
not Up-to-date 404413 195313 138586 70.96 599726 425541
DK/Missing 580695 220230 168116 76.34 800925 611399
Total 3285452 2325326 1922490 82.68 5610778 4604331 82.06
Provider-adjusted estimates
Children 19-35 months old
Weighted (weight = WTFA_IM)
4:3:1:3
Final
Final Provider
Number of Without Total With Provider adjusted
Doses Reported Provider Provider Up_to_ adjusted up-to-
By household Data Data date Percent Total up-to-date date(%)
Shot card, Up-to-date-Number 438214 613252 575668 93.87 1051466 987025
not Up-to-date 398856 451385 302301 66.97 850241 569422
No shot card, Up-to-date-All 1193749 691737 587659 84.95 1885486 1601798
Up-to-date -Number 63907 46765 35461 75.83 110672 83920
not Up-to-date 538099 272886 207624 76.08 810985 617034
DK/Missing 652627 249301 192778 77.33 901928 697438
Total 3285452 2325326 1901491 81.77 5610778 4556637 81.21
Provider-adjusted estimates
Children 19-35 months old
Weighted (weight = WTFA_IM)
4:3:1:3:3
Final
Final Provider
Number of Without Total With Provider adjusted
Doses Reported Provider Provider Up_to_ adjusted up-to-
By household Data Data date Percent Total up-to-date date(%)
Shot card, Up-to-date -Number 381825 547116 516761 94.45 928941 877402
not Up-to-date 455245 517521 310412 59.98 972766 583471
No shot card, Up-to-date -All 1038852 584207 472680 80.91 1623059 1313212
Up-to-date -Number 53167 36832 28527 77.45 89999 69706
not Up-to-date 685482 360738 247736 68.67 1046220 718489
DK/Missing 670881 278912 195969 70.26 949793 667343
Total 3285452 2325326 1772085 76.21 5610778 4229623 75.38
**************************************************************************************
SE_NIPR97.SAS
THIS PROGRAM WILL PRODUCE ESTIMATES AND STANDARD ERRORS FOR BEST VALUE
UP-TO-DATE STATUS USING SAS- CALLABLE SUDAAN.
SUDAAN NOTES:
1. ALL VARIABLES USED MUST BE NUMERIC.
2. VARIABLES IN THE SUBGROUP STATEMENT MUST HAVE VALUES 1,2,...K
WHERE K IS THE NUMBER OF LEVELS FOR EACH VARIABLE.
3. DATA MUST BE SORTED ACCORDING TO THE SAMPLE DESIGN VARIABLES
(STRATUM AND PRIMARY SAMPLING UNIT), SPECIFIED IN THE NEST STATEMENT.
***************************************************************************************;
title 'SUD_NIPR.SAS';
options nofmterr ls=80;
libname data ‘c:\nprpuf97’; **** SPECIFY PATH TO SAS DATA SET;
proc format ;
value utdf 1='UP-TO-DATE'
2='NOT UP-TO-DATE';
run;
data analyt;
set data.nprpuf97 /** SPECIFY NAME OF THE SAS DATA SET **/
(where=(19<=icagemr<=35 and bestval=1)); ** AGE 19-35 MO **
** AND HAVE BEST VALUE **;
/****
COLLAPSE STRATUM TO HAVE 2 PSU PER STRATUM
****/
if stratum in (1,2) then cstratum=400;
if stratum in (4,3,5) then cstratum=401;
if stratum in (8,9,10) then cstratum=402;
if stratum in (17,18) then cstratum=403;
if stratum in (23,24) then cstratum=404;
if stratum in (25,26) then cstratum=405;
if stratum in (32,33) then cstratum=406;
if stratum in (35,36,37,38,39,40,41) then cstratum=407;
if stratum in (42,43) then cstratum=408;
if stratum in (48,49) then cstratum=409;
if stratum in (50,51,52) then cstratum=410;
if stratum in (53,54) then cstratum=411;
if stratum in (55,56) then cstratum=412;
if stratum in (58,59) then cstratum=413;
if stratum in (64,65) then cstratum=414;
if stratum in (71,72) then cstratum=415;
if stratum in (74,75) then cstratum=416;
if stratum in (77,78) then cstratum=417;
if stratum in (81,82) then cstratum=418;
if stratum in (85,86) then cstratum=419;
if stratum in (88,89,90) then cstratum=420;
if stratum in (93,94) then cstratum=421;
if stratum in (98,99,100) then cstratum=422;
if stratum in (101,102,103,104) then cstratum=423;
if stratum in (107,108,109,110) then cstratum=424;
if stratum in (111,112) then cstratum=425;
if stratum in (114,115,116) then cstratum=426;
if stratum in (122,123) then cstratum=427;
if stratum in (125,126,127,129,130) then cstratum=428;
if stratum in (132,133) then cstratum=429;
if stratum in (135,136) then cstratum=430;
if stratum in (142,143) then cstratum=431;
if stratum in (145,146,147,148) then cstratum=432;
if stratum in (151,152) then cstratum=433;
if stratum in (153,154) then cstratum=434;
if stratum in (156,157,158) then cstratum=435;
if stratum in (160,161) then cstratum=436;
if stratum in (164,165) then cstratum=437;
if stratum in (167,168) then cstratum=438;
if stratum in (169,170,171,172) then cstratum=439;
if stratum in (176,177,180) then cstratum=440;
if stratum in (181,182) then cstratum=441;
if stratum in (186,187) then cstratum=442;
if stratum in (189,190) then cstratum=443;
if stratum in (194,196) then cstratum=444;
if stratum in (197,199) then cstratum=445;
if stratum in (202,203) then cstratum=446;
if stratum in (205,206) then cstratum=447;
if stratum in (207,208) then cstratum=448;
if stratum in (211,212) then cstratum=449;
if stratum in (214,215) then cstratum=450;
if stratum in (216,217) then cstratum=451;
if stratum in (218,219) then cstratum=452;
if stratum in (222,223,224,225) then cstratum=453;
if stratum in (230,232) then cstratum=454;
if stratum in (234,236,237) then cstratum=455;
if stratum in (238,239) then cstratum=456;
if stratum in (241,242) then cstratum=457;
if stratum in (244,245,246) then cstratum=458;
if stratum in (249,250) then cstratum=459;
if stratum in (252,253) then cstratum=460;
if stratum in (256,257) then cstratum=461;
if stratum in (258,259) then cstratum=462;
if stratum in (263,264) then cstratum=463;
if stratum in (265,266) then cstratum=464;
if stratum in (268,269,270) then cstratum=465;
if stratum in (271,272,273) then cstratum=466;
if stratum in (278,279,280,283,284,285) then cstratum=466;
if stratum in (289,290,291,292) then cstratum=467;
if stratum in (296,297) then cstratum=468;
if stratum in (299,300) then cstratum=469;
if stratum in (307,308,309) then cstratum=470;
if stratum in (311,312,313) then cstratum=471;
if stratum in (321,322) then cstratum=472;
if stratum in (314,315) then cstratum=473;
if stratum in (324,325) then cstratum=474;
if stratum in (328,329,330) then cstratum=475;
if stratum in (333,334) then cstratum=476;
if stratum in (335,336,337,338,339) then cstratum=477;
/*** DEFINE UP-TO-DATE STATUS FOR EACH VACCINE AND SERIES ***/
if b_numdtp>=4 then b_utddtp=1;
else b_utddtp=2;
if b_numdtp>=3 then b_utddt3=1;
else b_utddt3=2;
if b_numpol>=3 then b_utdpol=1;
else b_utdpol=2;
if b_nummmr>=1 then b_utdmmr=1;
else b_utdmmr=2;
if b_numhib>=3 then b_utdhib=1;
else b_utdhib=2;
if b_numhep>=3 then b_utdhep=1;
else b_utdhep=2;
if b_utddtp=1 and b_utdpol=1 and b_utdmmr=1 then b_utd431=1;
else b_utd431=2;
if b_utddtp=1 and b_utdpol=1 and b_utdmmr=1 and b_utdhib=1 then butd4313=1;
else butd4313=2;
if b_utddtp=1 and b_utdpol=1 and b_utdmmr=1 and b_utdhib=1 and b_utdhep=1
then but43133=1;
else but43133=2;
format b_ut: but: utdf.;
run;
proc sort; /* SORT BY NEST VARIABLES */
by cstratum psu;
run;
proc crosstab data=analyt filetype=sas design=wr; /* SUDAAN PROCEDURE */
weight wt_bv2;
nest cstratum psu/missunit;
subgroup b_utddtp b_utddt3 b_utdpol b_utdmmr b_utdhib b_utdhib b_utdhep
b_utd431 butd4313 but43133;
levels 2 2 2 2 2 2 2 2 2 2;
tables b_utddtp b_utddt3 b_utdpol b_utdmmr b_utdhib b_utdhib b_utdhep
b_utd431 butd4313 but43133 ;
output / filename=se tablecell=default replace;
run;
UNWEIGHTED DISTRIBUTION OF CHILDREN AGED 12-35 MONTHS IN THE 1997 NHIS/NIPRCS
BY SELECTED DEMOGRAPHIC CHARACTERISTICS
Immunization Shot Card No Shot Card With Provider No Provider
Demographic Supplement Users Data Data
Characteristic (n %) (n %) (n %) (n %) (n %)
Total 2622 940 1682 1074 1548
Age of Child
1. 12-18 462 17.6 186 19.8 276 16.4 173 16.1 289 18.7
2. 19-24 786 30.0 316 33.6 470 27.9 347 32.3 439 28.4
3. 25-29 568 21.7 186 19.8 382 22.7 239 22.3 329 21.3
4. 30-35 806 30.7 252 26.8 554 32.9 315 29.3 491 31.7
Gender of Child
1. Male 1378 52.6 483 51.4 895 53.2 557 51.9 821 53.0
2. Female 1244 47.4 457 48.6 787 46.8 517 48.1 727 47.0
Race/Ethnicity of Child
1. Hispanic 795 30.3 328 34.9 467 27.8 281 26.2 514 33.2
2. Black, nonHispanic 408 15.6 105 11.2 303 18.0 143 13.3 265 17.1
3. White, nonHispanic 1308 49.9 472 50.2 836 49.7 610 56.8 698 45.1
4. Other, nonHispanic 111 4.2 35 3.7 76 4.5 40 3.7 71 4.6
Poverty Status
1. Below 592 22.6 234 24.9 358 21.3 238 22.2 354 22.9
2. At or above 1610 61.4 609 64.8 1001 59.5 734 68.3 876 56.6
3. Unknown 420 16.0 97 10.3 323 19.2 102 9.5 318 20.5
Income
1. $20,000 and above 1644 62.7 588 62.6 1056 62.8 717 66.8 927 59.9
2. Less than $20,000 855 32.6 326 34.7 529 31.5 332 30.9 523 33.8
3. Unknown 123 4.7 26 2.8 97 5.8 25 2.3 98 6.3
Education of Mother
1. Less than High School 655 25.8 258 28.0 397 24.6 243 23.2 412 27.6
2. High School 647 25.5 207 22.5 440 27.2 246 23.5 401 26.9
3. Some College 741 29.2 256 27.8 485 30.0 328 31.4 413 27.7
4. College Graduate 466 18.4 197 21.4 269 16.6 228 21.8 238 16.0
5. Unknown 28 1.1 2 0.2 26 1.6 1 0.1 27 1.8
Immunization Shot Card No Shot Card With Provider No Provider
Demographic Supplement Users Data Data
Characteristic (n %) (n %) (n %) (n %) (n %)
Census Region
1. Northeast 495 18.9 164 17.4 331 19.7 206 19.2 289 18.7
2. Midwest 561 21.4 224 23.8 337 20.0 267 24.9 294 19.0
3. South 880 33.6 271 28.8 609 36.2 343 31.9 537 34.7
4. West 686 26.2 281 29.9 405 24.1 258 24.0 428 27.6
MSA
1. 5,000,000 or more 375 14.3 123 13.1 252 15.0 114 10.6 261 16.9
2. 2,500,000 - 4,999,999 323 12.3 124 13.2 199 11.8 128 11.9 195 12.6
3. 1,000,000 - 2,499,999 668 25.5 234 24.9 434 25.8 242 22.5 426 27.5
4. 500,000 - 999,999 292 11.1 108 11.5 184 10.9 137 12.8 155 10.0
5. 250,000 - 499,999 318 12.1 116 12.3 202 12.0 129 12.0 189 12.2
6. Under 250,000 216 8.2 83 8.8 133 7.9 93 8.7 123 7.9
7. Non-MSA 430 16.4 152 16.2 278 16.5 231 21.5 199 12.9
RACE
1. White 1897 72.3 713 75.9 1184 70.4 810 75.4 1087 70.2
2. Black 400 15.3 98 10.4 302 18.0 134 12.5 266 17.2
3. Asian 24 0.9 12 1.3 12 0.7 13 1.2 11 0.7
4. API 84 3.2 28 3.0 56 3.3 31 2.9 53 3.4
5. Other 115 4.4 53 5.6 62 3.7 45 4.2 70 4.5
6. Multiple race 79 3.0 23 2.4 56 3.3 33 3.1 46 3.0
7. Unknown 23 0.9 13 1.4 10 0.6 8 0.7 15 1.0
HISPAN_P
0. Multiple Hispanic 21 0.8 7 0.7 14 0.8 10 0.9 11 0.7
1. Puerto Rican 68 2.6 19 2.0 49 2.9 18 1.7 50 3.2
3. Mexican-Mexicano 153 5.8 65 6.9 88 5.2 54 5.0 99 6.4
4. Mexican-American 338 12.9 152 16.2 186 11.1 123 11.5 215 13.9
5. Cuban/Cuban-American 20 0.8 5 0.5 15 0.9 2 0.2 18 1.2
6. Other Latin American 64 2.4 25 2.7 39 2.3 17 1.6 47 3.0
7. Other Spanish 6 0.2 6 0.4 1 0.1 5 0.3
8. Hispanic/Spanish, non-spec 120 4.6 53 5.6 67 4.0 56 5.2 64 4.1
9-11. Hispanic/Spanish, unk 5 0.2 2 0.2 3 0.2 5 0.3
12. Non Hispanic/Spanish Orig 1827 69.7 612 65.1 1215 72.2 793 73.8 1034 66.8
WEIGHTED DISTRIBUTION OF CHILDREN AGED 12-35 MONTHS IN THE 1997 NHIS/NIPRCS
BY SELECTED DEMOGRAPHIC CHARASTERISTICS (WEIGHT = WTFA_IM)
Immunization Shot Card No Shot Card With Provider No Provider
Demographic Supplement Users Data Data
Characteristic (n %) (n %) (n %) (n %) (n %)
Total 7884812 2822991 5061821 3319169 4565643
Age of Child
1. 12-18 2274034 28.8 921284 32.6 1352750 26.7 885190 26.7 1388844 30.4
2. 19-24 1991588 25.3 778678 27.6 1212910 24.0 887410 26.7 1104178 24.2
3. 25-29 1506468 19.1 482553 17.1 1023915 20.2 661281 19.9 845187 18.5
4. 30-35 2112722 26.8 640476 22.7 1472246 29.1 885288 26.7 1227434 26.9
Gender of Child
1. Male 4117525 52.2 1497279 53.0 2620246 51.8 1728346 52.1 2389179 52.3
2. Female 3767287 47.8 1325712 47.0 2441575 48.2 1590823 47.9 2176464 47.7
Race/Ethnicity of Child
1. Hispanic 1402341 17.8 554638 19.6 847703 16.7 479516 14.4 922825 20.2
2. Black, nonHispanic 1126972 14.3 282706 10.0 844266 16.7 402446 12.1 724526 15.9
3. White, nonHispanic 4974409 63.1 1856338 65.8 3118071 61.6 2304301 69.4 2670108 58.5
4. Other, nonHispanic 381090 4.8 129309 4.6 251781 5.0 132906 4.0 248184 5.4
Poverty Status
1. Below 1515890 19.2 592482 21.0 923408 18.2 624202 18.8 891688 19.5
2. At or above 5192248 65.9 2001513 70.9 3190735 63.0 2423018 73.0 2769230 60.7
3. Unknown 1176674 14.9 228996 8.1 947678 18.7 271949 8.2 904725 19.8
Income
1. $20,000 and above 5365480 68.0 1970927 69.8 3394553 67.1 2401706 72.4 2963774 64.9
2. Less than $20,000 2197866 27.9 805494 28.5 1392372 27.5 855295 25.8 1342571 29.4
3. Unknown 321466 4.1 46570 1.6 274896 5.4 62168 1.9 259298 5.7
Education of Mother
1. Less than High School 1589486 20.7 565257 20.5 1024229 20.9 587791 18.1 1001695 22.7
2. High School 1962648 25.6 652164 23.6 1310484 26.8 799691 24.6 1162957 26.3
3. Some College 2302426 30.1 787185 28.5 1515241 30.9 1017144 31.3 1285282 29.1
4. College Graduate 1710591 22.3 750451 27.2 960140 19.6 837181 25.8 873410 19.8
5. Unknown 95522 1.2 8044 0.3 87478 1.8 3298 0.1 92224 2.1
NOTE: Weight WTFA_IM. For ages 12-18 months weight is multiplied by 2
Immunization Shot Card No Shot Card With Provider No Provider
Demographic Supplement Users Data Data
Characteristic (n %) (n %) (n %) (n %) (n %)
Census Region
1. Northeast 1608838 20.4 560561 19.9 1048277 20.7 686158 20.7 922680 20.2
2. Midwest 1921906 24.4 807085 28.6 1114821 22.0 927913 28.0 993993 21.8
3. South 2709826 34.4 789072 28.0 1920754 37.9 1074242 32.4 1635584 35.8
4. West 1644242 20.9 666273 23.6 977969 19.3 630856 19.0 1013386 22.2
MSA
1. 5,000,000 or more 928226 11.8 280235 9.9 647991 12.8 275447 8.3 652779 14.3
2. 2,500,000 - 4,999,999 999603 12.7 409151 14.5 590452 11.7 428737 12.9 570866 12.5
3. 1,000,000 - 2,499,999 2031642 25.8 704887 25.0 1326755 26.2 746732 22.5 1284910 28.1
4. 500,000 - 999,999 898760 11.4 320458 11.4 578302 11.4 436007 13.1 462753 10.1
5. 250,000 - 499,999 959500 12.2 359071 12.7 600429 11.9 400508 12.1 558992 12.2
6. Under 250,000 682163 8.7 263064 9.3 419099 8.3 285136 8.6 397027 8.7
7. Non-MSA 1384918 17.6 486125 17.2 898793 17.8 746602 22.5 638316 14.0
RACE
1. White 6003928 76.1 2263317 80.2 3740611 73.9 2630742 79.3 3373186 73.9
2. Black 1085473 13.8 259768 9.2 825705 16.3 376123 11.3 709350 15.5
3. Asian 71669 0.9 33924 1.2 37745 0.7 40420 1.2 31249 0.7
4. API 286375 3.6 102959 3.6 183416 3.6 100727 3.0 185648 4.1
5. Other 182994 2.3 80075 2.8 102919 2.0 69067 2.1 113927 2.5
6. Multiple race 218275 2.8 65887 2.3 152388 3.0 90597 2.7 127678 2.8
7. Unknown 36098 0.5 17061 0.6 19037 0.4 11493 0.3 24605 0.5
HISPAN_P
0. Multiple Hispanic 45330 0.6 10965 0.4 34365 0.7 20610 0.6 24720 0.5
1. Puerto Rican 135940 1.7 43123 1.5 92817 1.8 33216 1.0 102724 2.2
3. Mexican-Mexicano 247590 3.1 99754 3.5 147836 2.9 79620 2.4 167970 3.7
4. Mexican-American 579758 7.4 252146 8.9 327612 6.5 210186 6.3 369572 8.1
5. Cuban/Cuban-American 36291 0.5 10398 0.4 25893 0.5 5514 0.2 30777 0.7
6. Other Latin American 128275 1.6 45029 1.6 83246 1.6 31348 0.9 96927 2.1
7. Other Spanish 11952 0.2 11952 0.2 1402 0.0 10550 0.2
8. Hispanic/Spanish, non-spec 200634 2.5 86037 3.0 114597 2.3 97620 2.9 103014 2.3
9-11. Hispanic/Spanish, unk 16571 0.2 7186 0.3 9385 0.2 16571 0.4
12. Non Hispanic/Spanish Orig 6482471 82.2 2268353 80.4 4214118 83.3 2839653 85.6 3642818 79.8
Note: Weight WTFA_IM. For ages 12-18 months weight is multiplied by 2
DESCRIPTIVE STATISTICS FOR TWO SAMPLING WEIGHT VARIABLES INCLUDED IN 1997 NHIS/NIPRCS DATA FILE
ALL CHILDREN Aged 12-35 MONTHS IN IMMUNIZATION SUPPLEMENT
WEIGHT = WTFA_IM
NUMBER SUM OF MINIMUM MAXIMUM MEAN COEFFICIENT
CHILDREN WEIGHTS VALUE VALUE OF VARIATION
Total 2622 7884812 744 19088 3007.17 54.0920
Age of Child
1. 12-18 462 2274034 1574 19088 4922.15 46.2068
2. 19-35 2160 5610778 744 10795 2597.58 41.3751
Gender
1. Male 1378 4117525 788 16930 2988.04 55.3610
2. Female 1244 3767287 744 19088 3028.37 52.6998
Race/Ethnicity
1. Hispanic 795 1402341 744 7716 1763.95 51.1847
2. Black, nonHispanic 408 1126972 920 16930 2762.19 53.6576
3. White, nonHispanic 1308 4974409 916 19088 3803.06 40.3750
4. Other, nonHispanic 111 381090 1458 8023 3433.24 40.2722
CHILDREN AGED 12-35 MONTHS WITH BEST VALUES FOR DATES
WEIGHT = WT_BV2
NUMBER SUM OF MINIMUM MAXIMUM MEAN COEFFICIENT
CHILDREN WEIGHTS VALUE VALUE OF VARIATION
Total 1197 7884812.00 816.749 57591.54 6587.14 82.9717
Age of Child
1. 12-18 177 2274034.00 2049.90 57591.54 12847.65 65.8868
2. 19-35 1020 5610778.00 816.75 25918.34 5500.76 69.6875
Gender
1. Male 621 4133918.68 816.749 57591.54 6656.87 85.1606
2. Female 576 3750893.32 924.174 32547.94 6511.97 80.4830
Race/Ethnicity
1. Hispanic 331 1402341.00 816.75 26595.16 4236.68 91.0726
2. Black, nonHispanic 153 1126972.00 1340.79 45378.06 7365.83 83.6359
3. White, nonHispanic 671 5078440.16 1223.11 57591.54 7568.47 75.2167
4. Other, nonHispanic 42 277058.84 1420.74 18296.70 6596.64 65.4372
Note: Children aged 12-18 months were included in the 1997 NHIS Immunization Supplement only during quarters 3 and 4.
