Series 1

No. 36

Plan and Operation of the

1995 National Survey of Family

Growth

October 1997

Vital and

Health Statistics

From the CENTERS FOR DISEASE CONTROL AND PREVENTION / National Center for Health Statistics

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics
Copyright information

All material appearing in this report is in the public domain and may be

reproduced or copied without permission; citation as to source, however, is

appreciated.

Disclaimer

Brand names in this report are used solely for identification. Use of brand

names does not constitute endorsement of the equipment or product by NCHS

or any other government agency.

Suggested citation

Kelly JE, Mosher WD, Duffer AP, and Kinsey SH. Plan and operation of the

1995 National Survey of Family Growth. Vital Health Stat 1(36). 1997.

Library of Congress Catalog Card Number

Plan and operation of the 1995 National Survey of Family Growth.

p. cm. — (Vital and health statistics. Ser. 1, Programs and collection

procedures ; no 36) (DHHS publication ; no. (PHS) 98-1312)

By J.E. Kelly ... [et al.].

Includes bibliographical references.

ISBN 0-8406-0531-5

1. Family size—United States—Statistical methods. 2. Birth control

—United States—Statistical methods. 3. Family life surveys—United States. 4.

Health surveys—United States. I. J.E. Kelly. II. Series. III. Series: DHHS

publication ; no (PHS) 98-1312.

[DNLM: 1. National Survey of Family Growth (U.S.). 2. Family

Planning—United States. 3. Interviews—methods. 4. Health Surveys—United

States. W2 A N148va no.36 1997]

RA409.U44 no. 36

[HQ766.5.U5]

362.1'0723 s—dc21

[304.6'34'0973]

DNLM/DLC 97-36607

for Library of Congress CIP

For sale by the U.S. Government Printing Office

Superintendent of Documents

Mail Stop: SSOP

Washington, DC 20402-9328

Printed on acid-free paper.
Plan and Operation of the

1995 National Survey of Family

Growth

Series 1:

Programs and Collection Procedures

No. 36

Hyattsville, Maryland

October 1997

DHHS Publication No. (PHS) 98-1312

Vital and

Health Statistics

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics
National Center for Health Statistics

Edward J. Sondik, Ph.D., Director

Jack R. Anderson, Deputy Director

Jack R. Anderson, Acting Associate Director for

International Statistics

Lester R. Curtin, Ph.D., Acting Associate Director for

Research and Methodology

Jacob J. Feldman, Ph.D., Associate Director for Analysis,

Epidemiology, and Health Promotion

Gail F. Fisher, Ph.D., Associate Director for Data Standards,

Program Development, and Extramural Programs

Edward L. Hunter, Associate Director for Planning, Budget,

and Legislation

Jennifer H. Madans, Ph.D., Acting Associate Director for

Vital and Health Statistics Systems

Stephen E. Nieberding, Associate Director for

Management

Charles J. Rothwell, Associate Director for Data

Processing and Services

Division of Vital Statistics

Mary Anne Freedman, Director

James A. Weed, Ph.D., Deputy Director

Kenneth G. Keppel, Ph.D., Acting Chief, Reproductive

Statistics Branch

Nicholas F. Pace, Chief, Systems Programming and

Statistical Resources Branch
Contents

Abstract ................................................................................................ 1

Planning and Development of Cycle 5 of the National Survey of Family Growth .................................... 1

Introduction .......................................................................................... 1

A Brief Chronology .................................................................................... 2

Major Changes in Cycle 5 of the National Survey of Family Growth ............................................ 3

Changes That Were Not Made ........................................................................... 7

Summary ............................................................................................ 7

The National Survey of Family Growth Pretest ................................................................ 7

Interview Mode Effects ................................................................................. 8

Incentive Effects....................................................................................... 8

Main Study Design Decisions............................................................................ 9

Sample Design .......................................................................................... 9

Overview ............................................................................................ 9

Design of the National Health Interview Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

National Survey of Family Growth Sampling Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Sampling Procedure and Allocations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Sample Sizes, Selection Probabilities, and Response Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Tracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Tracing of Sampled Women . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Completeness of Locator Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Results of Advance Tracing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Field Tracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Central Office Tracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

U.S. Bureau of the Census Tracing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Questionnaire Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Pretest Questionnaire Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Revisions to the Questionnaire for the Main Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

CAPI and Audio CASI Development for the Main Study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Spanish Translation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Interviewer Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Manuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Materials Used for Locating and Contacting Respondents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Materials Used for Obtaining Participation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Computer Hardware, Audio CASI Hardware, and Related Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Materials Used To Administer the Interview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

iii
Interviewer Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Training Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Data Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Field Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Interviewer Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Interviewing Sample Women. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Data Collection Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Interview Length, Tracing, and Response Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Quality Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Practice, Monitoring, and Evaluation at Training. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Interview Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Data Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

In-house Survey Control System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Field Monitoring System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Field Reports System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Data Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Data Editing Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Data Coding Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Data File Creation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Data File Documentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Appendix I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Definitions of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Appendix II. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Outline of the Contents of the 1995 National Survey of Family Growth Questionnaire. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Appendix III . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Generic Lead Letters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Appendix IV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Contact Scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Appendix V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Authorization Letter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Appendix VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Question and Answer Brochure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Appendix VII . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Life History Calendar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Appendix VIII. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Field Interview Training Agenda. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Appendix IX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Summary Tables of Data Collection Status Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Figures

1. Chronology of Cycle 5 of the National Survey of Family Growth ............................................ 2

2. Principal people involved in the design and planning of Cycle 5 of the National Survey of Family Growth .......... 3

3. Outline of the 1995 National Survey of Family Growth Questionnaire ........................................ 4

4. Example pages from the CAPI Reference Questionnaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

iv
5. Significant revisions in the National Survey of Family Growth questionnaire after the pretest. . . . . . . . . . . . . . . . . . . . . 22

6. Example summary screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

7. Examples of interviewer comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Text Tables

A. Number of women eligible for the National Survey of Family Growth Pretest, by interview mode and incentive ...... 8

B. Response rates for the Pretest, by incentive .............................................................. 9

C. Estimated design effects and sample sizes for National Survey of Family Growth Cycles 3, 4, and 5. . . . . . . . . . . . . . . 11

D. Distribution of National Health Interview Survey clusters and households, by cluster composition strata . . . . . . . . . . . . 12

E. Sample sizes, probability of selection, and average weight, and relative variance of weights, by race/ethnicity and

number of eligible women: 1995 National Survey of Family Growth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

F. Response rates for Cycle 5 of the National Survey of Family Growth among completed cases in the National Health

Interview Survey, by race/ethnicity and age: 1995 National Survey of Family Growth. . . . . . . . . . . . . . . . . . . . . . . . . . . 13

G. Clustering and weight variation for completed interviews by race/ethnicity and age: 1995 National Survey of Family

Growth Cycle 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

H. Tracing steps in the 1995 National Survey of Family Growth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

J. Summary of missing locator information from the National Health Interview Survey in the sample for the 1995

National Survey of Family Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

K. Final results of advance tracing operation: August–November, 1994 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

L. Percent not located in the 1995 National Survey of Family Growth, by selected characteristics . . . . . . . . . . . . . . . . . . . 16

M. Results of central office tracing efforts: 1995 National Survey of Family Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

N. Results of U.S. Bureau of the Census tracing, by final field interview status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

O. Final results of field tracing: 1995 National Survey of Family Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

P. Unweighted sample sizes in the 1995 National Survey of Family Growth, by race/ethnicity and age . . . . . . . . . . . . . . . 18

Q. The number of sample women and estimated number of field interviewers by supervisory regions as assessed in

1994 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

R. Percent unlocatable, percent refused, and response rate, by race/ethnicity and National Health Interview Survey

income: 1995 National Survey of Family Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

S. Mean (average) and estimated mean time (minutes) required to complete the interview, by section of the

questionnaire: 1995 National Survey of Family Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

v
Objectives

This report describes how the 1995

National Survey of Family Growth

(NSFG) was designed, planned, and

implemented. The NSFG is a national

survey of women 15–44 years of age

designed to provide national estimates

of factors affecting pregnancy and birth

rates and the health of women and

infants. Planning for the 1995 NSFG

began in 1990 at a formal conference

with the survey’s data users.

Suggestions for substantial changes

and improvements in the survey were

made there and carried out by NSFG

staff and the NSFG contractor—the

Research Triangle Institute (RTI).

Methods

The survey was converted from

paper and pencil interviewing to

Computer-Assisted Personal

Interviewing (CAPI) to improve the

quality, consistency, and timeliness of

the data. At the same time, event

histories of the respondent’s work,

education, family background,

cohabitation, and sexual partners were

added to lend explanatory power to the

survey. These changes made the

interview and the CAPI program

long—average interview length was 103

minutes—and complex, but the CAPI

program worked very well.

Results

About 260 female interviewers were

trained for 7 days in January 1995.

These interviewers completed a total of

10,847 interviews with women 15–44

years of age, for a response rate of

79 percent. This report describes how

the survey was planned and designed

and how the data were collected,

edited, and processed for public use.

This report may be of interest to NSFG

data users and to those planning other

computer-assisted surveys.

Keywords: survey methodology c

computer-assisted interviewing c

interviewer training c fieldwork c

(interviewing)

Plan and Operation of the 1995

National Survey of Family

Growth

by Janice E. Kelly, Research Triangle Institute, William D. Mosher,

Ph.D., Division of Vital Statistics, Allen P. Duffer, Jr., and Susan H.

Kinsey, Research Triangle Institute

Planning and

Development of

Cycle 5 of the

National Survey of

Family Growth

Introduction

The National Survey of Family

Growth (NSFG) is a survey

conducted by the National

Center for Health Statistics (NCHS).

NCHS is one of the Centers for Disease

Control and Prevention (CDC). The

NSFG is designed to make national

estimates of factors affecting birth and

pregnancy rates in the United States.

NCHS has conducted the NSFG

since 1973. Interviewing for the first

NSFG (called Cycle 1) was conducted

in 1973; 9,797 women 15–44 years of

age were interviewed. For the second

NSFG (Cycle 2), 8,611 interviews were

completed in 1976. The 1973 and 1976

NSFG surveys were restricted to women

who were currently or formerly married

(separated, divorced, or widowed).

After Cycle 2, the NSFG was

redesigned to include women who had

never been married. The third NSFG

(Cycle 3) was conducted in 1982; 7,969

interviews were obtained from women

15–44 years of age regardless of marital

status. The fourth NSFG was conducted

in 1988 and yielded 8,450 interviews.

Interviews in Cycles 1, 2, and 3

averaged about 60 minutes, and in Cycle

4, interviews averaged about 70

minutes. From these surveys, more than

200 reports and articles were published

on sexual activity, contraceptive use, the

effectiveness of contraceptives,

cohabitation, marriage and divorce,

infertility, use of family planning and

other health services, and many other

topics (1–3).

These statistics have been very

useful for many purposes, but changes

in society and advances in research

raised new questions for fertility surveys

to answer. Thus, in the late 1980’s, the

agencies and individuals who used

NSFG data concluded that major

improvements in the NSFG were needed

if the survey was going to meet the data

needs of the 1990’s and beyond.

This report describes the planning

of the 1995 NSFG and how the survey

was carried out. The information in this

report may be useful to those interested

in applying the experience of the NSFG

in planning other major surveys, as well

as those who have a substantive interest

in the topics covered by the NSFG. The

technical terms used in this report are

defined in appendix I.

The planning, development, and

execution of Cycle 5 of the NSFG was

The 1995 National Survey of Family Growth was jointly planned and funded primarily by the National

Center for Health Statistics, the National Institute for Child Health and Human Development, and the

Office of Population Affairs, with additional support from the Administration for Children and Families.

Other agencies and individuals also provided helpful advice and assistance.

Page 1
a 7-year process that required the efforts

of many people and organizations

working together. This report cannot

identify all of the persons or

organizations involved, but NCHS

extends its thanks to all of them. The

brief summary of the planning for Cycle

5 given in this report will only attempt

to note some of the major developments

in the study, particularly in connection

with the formal meetings that NCHS

staff held with other organizations and

individuals. A great deal of informal

communication and consultation took

place between these formal meetings.

Major funding for the 1982, 1988, and

1995 NSFG’s was provided by three

parts of the U.S. Department of Health

and Human Services (DHHS):

+ the National Center for Health

Statistics (NCHS)

+ the Office of Population Affairs

(OPA)

+ the National Institute for Child

Health and Human Development

(NICHHD)

In addition, funding for questions on

adoption was obtained from the

Administration for Children and

Families.

A Brief Chronology

In the late 1980’s, the agencies

cosponsoring the NSFG decided that a

thorough assessment of the role and

content of the survey was needed. On

February 5–6, 1990, NCHS convened a

2-day conference on ‘‘The National

Survey of Family Growth: Mission for

the 1990’s’’ with about 50 invited

participants drawn from several DHHS

agencies, universities, and private

research organizations. The purpose was

to solicit advice on the direction the

survey should take in the 1990’s

(figure 1).

During 1990 and 1991, NSFG staff

reviewed the recommendations of the

February 1990 Conference and began to

draft a questionnaire for Cycle 5.

Figure 2 is a partial list of those

involved in Cycle 5 planning, beginning

with the conference in February 1990.

Not all NCHS staff listed were present

throughout the period, and not all

persons consulted are listed in figure 2.

Throughout the planning and

development of the 1995 NSFG, NSFG

staff had several interrelated tasks: to

assess data needs, to make decisions

about the relative priority of the many

questions or changes requested, and to

decide on the best ways to implement

them to ensure that the NSFG’s

substantive objectives were met. NSFG

staff based these decisions on the

comments of outside experts, their own

knowledge of the field, their contacts

with interested government agencies and

with researchers inside and outside

government, and their experience using

the NSFG for research.

On April 5, 1991, NCHS hosted a

1-day meeting with 6 NCHS staff and

10 invited experts to discuss a draft

questionnaire prepared by NCHS staff.

Revisions were made in the months

following that meeting, and on May 15,

1992, a 1-day meeting with 15 invited

participants was held to conduct the

final review of the Cycle 5 questionnaire

before it was submitted to the NCHS

Institutional Review Board (IRB) and to

the Office of Management and Budget

(OMB) for clearance.

In September 1992, the contract for

Cycle 5 was awarded to the Research

Triangle Institute (RTI) of Research

Triangle Park, North Carolina. In the

following year (October

1992—September 1993), the

specifications for the questionnaire were

developed, the CAPI questionnaire was

programmed, tested extensively by both

RTI and NCHS, and preparations for the

pretest were made. During

October–December 1993, 500 interviews

were conducted with women in three

Figure 1. Chronology of Cycle 5 of the National Survey of Family Growth

Page 2 [ Series 1, No. 36
States in the NSFG Pretest. The CAPI

program worked very well in the pretest,

despite an average interview length of

nearly 2 hours. The pretest was designed

as an experiment; the results showed

that incentives for respondents improved

response rates, reduced survey costs,

and increased abortion reporting (4–6).

(See the section on ‘‘The National

Survey of Family Growth Pretest’’ for

more details.)

On January 18–19, 1994, a 2-day

workshop with 7 NCHS staff and 11

others was held to review the results of

the pretest and make recommendations

for the main study. While no major

changes were made in the content of the

survey, a large number of technical

improvements were recommended. RTI

and NCHS evaluated the workshop

recommendations and decided on a

revised schedule. (See the section on

‘‘Questionnaire Development’’ for more

details.)

In January 1995, 253 interviewers

were trained for the NSFG, and

interviewing began nationwide.

Interviewing continued until the end of

October 1995. Interviews were

completed with 10,847 women,

including 1,553 Hispanic women, 2,446

black women, 6,483 white women, and

365 others. The mean length of

interview in the main study was 103

minutes (or 1 hour and 43 minutes). The

final response rate was 79 percent. The

two principal causes of nonresponse

were refusals (11 percent) and inability

to locate sampled women who had

moved since the 1993 National Health

Interview Survey (NHIS) (5 percent).

(See ‘‘Interviewer Materials,’’

‘‘Interviewer Training,’’ and ‘‘Data

Collection’’ for more details.)

The NSFG staff spent 1996 working

with the contractor on such data

preparation tasks as coding ‘‘other

(specify)’’ responses; resolving

inconsistencies in the data; constructing,

reviewing, and editing ‘‘recoded’’ variables;

imputing missing data; constructing

sampling weights for each case; and

preparing documentation for the data

file—such as variable labels, value labels,

descriptions of which respondents were

asked each question, and a detailed user’s

guide to accompany the codebook. Tables

were run on several preliminary data files

to test the quality and consistency of the

data. Apparent inconsistencies were

identified and corrected where necessary.

Highest priority was given to releasing a

high-quality data set as soon as possible.

(See ‘‘Data Preparation’’ for additional

details.)

Major Changes in Cycle 5

of the National Survey of

Family Growth

The 1995 NSFG includes at least 10

major changes when compared with the

1988 survey. This section reviews those

major changes and some of the factors

that were considered in making them.

1. Event Histories

Virtually all those consulted for

Cycle 5 recommended a dramatic

increase in the number and depth of

independent (or predictor) variables on

the NSFG. It was suggested that

50 percent of the survey should be

independent variables and that most of

those should be collected as event

histories. An event history is simply a

list of all the occurrences of some event,

with the beginning and ending dates of

each and other significant details. Event

histories are useful because they help to

sort out the temporal order, and thus the

causal sequences, in the data. That

makes it possible to test theories about

the causes of outcomes—such as early

sexual activity, effective and ineffective

contraceptive use, teenage pregnancy,

and unwanted births.

Figure 2. Principal people involved in the design and planning of Cycle 5 of the National

Survey of Family Growth

Series 1, No. 36 [ Page 3
The following event histories were

suggested:

+ a school attendance history

(separately for regular school,

general equivalency diploma (GED),

and vocational schooling)

+ a work history (periods working and

not working, but not occupations)

+ a history of the parents or guardians

the woman lived with during her

childhood

+ a cohabitation history and a sexual

partner history to complement the

marriage and divorce history

A life history calendar was also

suggested to collect and organize this

information.

It was understood that these

histories would make the interview

longer than the 60–70 minutes in Cycles

1–4. But a consensus was reached that

complete event histories on a wide

range of independent variables were

necessary in order to make the survey

maximally useful for both academic and

policy research in the years ahead. The

NSFG staff, funding agencies, and

outside researchers agreed that the cost

and effort required would be justified by

the increased usefulness of the data. As

shown in figure 3, all of these event

histories were added to the NSFG

Questionnaire.

The event histories had at least

three important effects on the 1995

NSFG:

+ The survey became much more

useful for academic and policy

research.

+ The length of the interview and the

size of the data file increased

dramatically.

+ Specifying, programming, and

testing these multiple event histories

became very challenging.

2. National Health Interview

Survey Variables

A second step in enriching the

NSFG for explanatory research was to

add some variables from the 1993 NHIS

on the women sampled in the NSFG.

This was possible because the sampling

frame for the 1995 NSFG was the 1993

NHIS.

NSFG staff and other experts

concluded that having NHIS variables

on the NSFG file could be useful

because (a) the detailed background data

on the NHIS allows for more precise

nonresponse adjustments than in an

independent sample, and thus more

accurate weights; (b) studies using

linked NHIS and NSFG data may be

useful for demographic and sociological

research on the family; (c) studies of

health issues (including the effects of

changes in the health care system) may

be enhanced by using NHIS and NSFG

data in the same analyses; and (d)

combining NHIS data from 1993 and

NSFG data from 1995 lends a

longitudinal aspect to the NSFG. As a

result, most of the data from the NHIS

core questionnaire were added to the

NSFG data file. These variables measure

health and demographic characteristics

of the NSFG respondent, her husband (if

she was married at the time of the

NHIS), and her household. This

‘‘linkage’’ between the NHIS and the

NSFG had very significant effects on

how the NSFG was conducted. Those

effects are discussed in the sections on

‘‘Tracing’’ and ‘‘Fieldwork’’ in this

report. In addition, some characteristics

of the NSFG interviewer were added,

permitting another set of factors to be

considered in causal models of response.

Figure 3. Outline of the 1995 National Survey of Family Growth Questionnaire

Page 4 [ Series 1, No. 36
3. Data on Men

Since Cycle 1 in 1973, the NSFG

has collected a marriage and divorce

history that included characteristics of

the woman’s husband(s). In those two

decades, however, births to unmarried

women have increased, many women

have postponed marriage, unmarried

cohabitation has increased, the age at

first intercourse has dropped, and

interest in men’s roles in teenage

pregnancy, child care, and child support

has increased. These changes made it

necessary for the NSFG to collect data

on the characteristics of the respondent’s

male sexual partners, regardless of her

marital status. To enhance the reliability

of the answers and reduce respondent

burden, however, questions on husbands,

cohabiting partners, and noncohabiting

sexual partners were limited in two

ways:

+ Basic demographic characteristics of

the male were limited to his age,

race, Hispanic origin, education,

religion, the importance of religion

to him, and the type of relationship

they had when they began having

intercourse (just met, just friends,

going together, going steady,

engaged, married).

+ The history of sexual partners was

limited to the 4 years immediately

before the interview (January 1991

to the interview date).

Similar questions were also asked about

the woman’s partner at her first

voluntary intercourse. A question was

also added on the age of the man who

fathered each of the woman’s

pregnancies. These questions will fill

some critical information gaps on the

role of men in fertility and

contraception.

It was also clear that data were

needed on the roles of fathers in family

life. New data were collected on the

dates, if any, when the respondent lived

with her father when she was growing

up, and if he left the household, why he

left (separation, divorce, death, illness,

other). Data were also added on receipt

of child support for the respondent’s

children under 18, and on the man’s role

in providing child care and health

insurance.

4. Contextual Data

A final and crucial step in the effort

to increase the number and range of

predictor variables in the NSFG was to

create a file of contextual (community

level) variables—measured at the State,

county, census tract, and block group

level. Many of those consulted requested

that NCHS prepare a contextual data

file. The term ‘‘Contextual’’ data refers

to data on the social ‘‘context,’’ or

environment, in which survey

respondents live. Some contextual

variables such as the unemployment

rate, the percent of the population that

lives in households below the poverty

level, or the number of family planning

clinics in the area, can be changed by

public policy, so contextual data are of

great practical importance. In addition, it

has been shown that contextual variables

do affect outcomes such as age at first

intercourse, contraceptive use, and

marriage and divorce (7,8).

Some contextual data come from

the summary tape files of the 1990 U.S.

Census, which contain data at the

county, census tract, and block group

level. Other contextual data measure

crime rates, rates of certain diseases,

and government policies and

expenditures, and may be coded at the

State or county level. Consultants

suggested that, if possible, the

respondent’s address should be coded at

the time of the 1990 Census as well as

at the date of interview in 1995, and this

was done in the NSFG contextual data

file. Because of the confidentiality

concerns they raise (9), the contextual

data will not be part of the public-use

data file. Qualified researchers who want

to use the contextual data should contact

NCHS to discuss how to apply for

access.

5. Computer-Assisted Personal

Interviewing (CAPI)

Many paper and pencil

questionnaires, especially those for

complex surveys, have ambiguous

concepts and routings. These ambiguous

features can create occasional confusion

and the potential for inconsistent

responses that have to be dealt with in

coding and editing after the interviewing

is over. CAPI software programs cannot

tolerate this kind of ambiguity, and

CAPI programmers must ask survey

designers to specify how to deal with

every contingency.

This ‘‘questionnaire specification’’

process clarifies the intent and logic of

questions and decreases

misinterpretations. These clearer

specifications and the automation of skip

patterns and routing through the

questionnaire increase the quality of the

data. Higher data quality and the

automation of most coding permit faster

processing of the data file after the

interviewing is completed.

However, specifying, programming,

and testing a CAPI questionnaire

requires more labor before interviewing

can begin than does a paper and pencil

questionnaire. The more complex the

questionnaire, the greater the time,

effort, and cost that must be devoted to

specifying and testing the questionnaire

program.

As noted previously, a consensus

was reached that comprehensive event

histories were necessary in the 1995

NSFG. However, specifying and

programming these histories was a

formidable task. For example, the

questionnaire program had to allow for

up to:

+ 11 periods of college attendance

+ 11 periods of GED attendance (4

was the most reported)

+ 11 periods of vocational school

attendance

+ 10 periods of employment

+ 10 periods of unemployment

+ 12 periods of living with her

mother; 12 periods of living with

her father; and 12 periods of living

with her grandparents

+ 10 periods of living alone (8 was

the most reported)

+ 10 periods of living with parents

again after living ‘‘on your own’’ (9

was the most reported)

+ 15 pregnancies

+ 20 children the woman raised who

were not born to her

+ 5 marriages

+ 9 cohabitations (including the

current one)

+ 36 sexual partners in the 5 years

before the survey

Series 1, No. 36 [ Page 5
+ 4 contraceptive methods used in the

month prior to each of the 15

pregnancies

+ 4 contraceptive methods used in

each of 58 months in the method

calendar (January 1991–October

1995).

As a result of this complexity, types

of academic and policy research are

now possible that were not possible in

any previous NSFG, but specification,

programming, and testing of the CAPI

questionnaire became very large jobs.

The interviews averaged 103 minutes in

length and varied from 20 minutes to 4

hours, increasing refusal rates compared

with previous cycles of the NSFG. Also,

the data file grew enormously. For

example, the respondent part of the

Cycle 5 data file has a record length of

over 13,000 compared with 2,753 in

Cycle 4—a fivefold increase.

6. Abortion Reporting

The NSFG is a survey about

pregnancy. Comparisons with vital

statistics suggest that reporting of live

births in the NSFG is very good.

Comparisons with other surveys suggest

that reporting of miscarriages and

stillbirths is also good. But respondents

in almost all fertility surveys, including

the NSFG, do not report all of their

abortions. Comparisons with external

data suggested that in the 1976 and

1982 NSFG’s, married women reported

only about one-half of the abortions

they had had. In the 1988 survey, it

appeared that women reported only

about one-third of their abortions

(10,11). The Cycle 5 contractor, RTI,

suggested using a self-administered

interview delivered over headphones to

attempt to collect more complete data

on abortion. This technique is called

Audio Computer-Assisted SelfInterviewing, or Audio CASI. Data from

the NSFG Pretest suggested that using

both Audio CASI and $20 incentives

increased reporting—but reporting was,

apparently, still not complete (4–6).

A pilot study for the NSFG,

conducted by the National Opinion

Research Center (NORC) in Chicago for

NCHS, investigated some other possible

ways to increase reporting. That study

confirmed that self-administered

questionnaires increased the reporting

of sensitive behavior, but did not

identify any other techniques that

appeared to increase reporting. After

further refinement, however, the

techniques used in the pilot study may

increase reporting of sensitive data in

future surveys if operationalized

differently (12).

7. Sample Size

Budget shortfalls made it necessary

to reduce sample size in both 1982 and

1988, but it was clear that these sample

sizes were making it impossible to do

certain kinds of analysis. In particular,

much larger samples of Hispanic

women, teenage women, and adult white

women were requested. Some

recommended much larger samples of

teenagers; for example, a sample of

2,500 women 15–19 years of age would

be necessary to compute reliable

estimates for white, black, and Hispanic

teenagers by single years of age—15,

16, 17, 18, and 19. Others urged NCHS

to increase the number of adult white

women in the sample substantially in

order to study issues such as delayed

childbearing, infertility, use of infertility

treatment, adoption, the timing of births

by parity, and other topics.

In response to these requests,

NCHS took the following steps:

+ Efforts were made to raise funds to

increase the NSFG sample size to

18,000, but these fundraising efforts

were not successful.

+ Given that the sample size could not

be increased across the board,

NCHS decided to oversample black

and Hispanic women by selecting all

households containing black and

Hispanic women 15–44 years of age

in the 1993 NHIS for the NSFG.

+ Given the difficulty of tracing

women in the pretest who moved,

NCHS directed RTI to select a

reserve sample of 875 eligible

women. Thus, the number of women

eligible for the NSFG was increased

from 13,125 to 14,000 to increase

the chances that the target sample

size of 10,500 completed interviews

would be met.

+ NCHS decided to extend the NSFG

fieldwork period from July 31, 1995,

to October 31, 1995, to allow for

more time for tracing and refusal

conversion.

These efforts did meet the goal of at

least 10,500 interviews: the final sample

size was 10,847, a 28-percent increase

over the 8,450 interviews in Cycle 4.

This overall size included 1,553

Hispanic women, 2,446 non-Hispanic

black women, 6,483 non-Hispanic white

women, and 365 women of other races

and origins.

8. Contraceptive Use and

Wantedness

The role of condom use in

preventing the transmission of the

human immunodeficiency virus (HIV),

the rising numbers of births to

unmarried teens and their connections

with welfare, and other factors

strengthened interest in better measures

of contraceptive use and unintended

pregnancy. Estimating the probability of

having an unintended pregnancy

(‘‘failure rates’’) for users of various

contraceptive methods has always been

one of the more important uses of

NSFG data (1,11).

It was agreed that the NSFG needed

to continue the basic trend data on

contraceptive use and efficacy, and also

collect new data to measure three

increasingly important aspects of

contraceptive use: (a) the consistency of

contraceptive use (whether

contraceptives are used at each act of

intercourse); (b) multiple method use

(using more than one method at a time,

or alternating methods with different

partners or according to the monthly

cycle); and (c) whether birth control

methods are being used to prevent

pregnancy, to prevent sexually

transmitted diseases, or for medical uses

such as treatment of menstrual pain. In

addition, the existing time series on

unintended pregnancy was continued,

while new data were added to measure

the strength and consistency (or

ambivalence) in women’s feelings about

their pregnancies (13).

Page 6 [ Series 1, No. 36
9. First Intercourse

There was an urgent need for recent

national data on the circumstances under

which first intercourse occurs. Questions

distinguishing whether the first

intercourse was voluntary or

nonvoluntary and the characteristics of

the first partner were recommended.

While some disagreed, most of those

consulted said that the information on

whether the first intercourse was

voluntary could be collected reliably,

citing the experience of the National

Survey of Children (14).

Ultimately, the NSFG staff decided

to collect the demographic

characteristics of the first voluntary

partner—his age, race, education,

marital status, and the type of

relationship (just met, just friends, going

out once in a while, going steady,

engaged, or married)—and to measure

the ‘‘voluntariness’’ of intercourse in

three different ways: (a) by having the

respondent rate how much she wanted

her first intercourse to happen at that

time on a scale of 1 to 10, (b) to

classify her first intercourse as

‘‘voluntary’’ or ‘‘not voluntary,’’ and (c)

to ask a separate self-administered

question on whether she had ever been

‘‘forced by a man to have sexual

intercourse against your will.’’

10. Use of Family Planning

Services

OPA is required to report to

Congress annually on the number of

women in need of family planning

services, the number and proportion of

those in need who are being served, and

the demographic and health

characteristics of those who use the Title

X family planning program. The NSFG

data on the populations using Title X

clinics, other clinics, and private doctors

for family planning services are,

therefore, important and useful data. As

a result, the NSFG staff and RTI

devoted considerable effort to improving

the questions on the source of family

planning services. This effort included a

written cognitive appraisal of the

questions, revision and testing of the

questions in the NCHS and RTI survey

methods laboratories, and use of an

external, national computerized database

of family planning clinics. (See ‘‘Data

Collection’’ and ‘‘Data Processing’’ for

more details.)

Changes That Were Not

Made

Many other recommendations were

made that could not be implemented in

Cycle 5—because of budgetary reasons,

because of practical difficulties in

carrying them out, or because they were

judged to be less urgent than those

described previously. Among these were:

+ requests for a further increase in

sample size, which was postponed

because of its cost

+ requests for longitudinal data,

postponed because of the costs and

practical difficulties of collecting

valid data with good response rates

+ including women 13–14 years of

age and 45–54 years of age in the

survey, which was postponed

because it was judged a lower

priority than increasing the sample

size of women 15–44 years of age,

and less urgent than the innovations

that were implemented in Cycle 5

+ conducting the survey more

frequently, postponed because of its

cost

+ including men in the survey, which

was postponed because of the

difficulty and cost of specifying

what information should be

collected and the need for research

on ways of obtaining good response

rates and high data quality from

male respondents.

These and other innovations will be

considered for later cycles of the NSFG.

Summary

Compared with Cycle 4, a long list

of major improvements were made in

Cycle 5 of the NSFG. The principal

changes discussed in this section were:

1. event histories

2. data from the NHIS

3. data on husbands, cohabiting

partners, and other male sexual

partners

4. contextual data

5. Computer-Assisted Personal

Interviewing (CAPI)

6. Audio CASI to improve data on

abortion and other sensitive topics

7. increased sample size

8. improved measures of contraceptive

use and wantedness

9. new data on first intercourse

10. efforts to improve data on use of

family planning services

For Cycle 5, 10,847 interviews were

completed, including 1,553 with

Hispanic women; 2,446 with black

women; 6,483 with white women; and

365 women of other races and origins.

The mean length of interview was 103

minutes (or 1 hour and 43 minutes). The

final response rate was 78.6 percent. The

two principal causes of nonresponse

were refusals (11 percent) and inability

to locate sampled women who had

moved since the 1993 NHIS (5 percent).

In Cycle 5 of the NSFG, a good

response rate was obtained, and

high-quality data were collected,

processed, and released in a timely

fashion, despite a very large increase in

the length and complexity of the

questionnaire and the introduction of

CAPI and Audio CASI technology. The

rest of this report describes how this

landmark study was conducted. It is

hoped that users of NSFG data and

those interested in survey methodology

will benefit equally from this account of

the NSFG experience.

The National Survey

of Family Growth

Pretest

After the NSFG Cycle 5 contract

was awarded in fall 1992, work

proceeded on two major tasks:

specifying, programming, and testing the

CAPI questionnaire (described in the

section on ‘‘Questionnaire Development’’) and designing the pretest. This

section describes briefly how the NSFG

pretest was designed, what was learned

from it, and how that learning was used

in the 1995 main study. More detailed

reports on the 1993 NSFG pretest have

been published elsewhere (4–6,15).

Series 1, No. 36 [ Page 7
The Cycle 5 pretest was designed to

test a number of significant innovations

in the study. These included:

+ computer-assisted personal

interviewing (CAPI)

+ audio computer-assisted

self-interviewing (Audio CASI)

+ interviewing sample women at

neutral sites

+ incentives.

To test the effect of these

innovations on the quality of the data

and the cost of data collection, sample

women were assigned to one of the

following five groups:

+ in-home CAPI administration of the

entire questionnaire—no incentive

+ in-home CAPI administration of the

entire questionnaire—$20 incentive

+ in-home CAPI administration with

one Audio CASI section—no

incentive

+ in-home CAPI administration with

one Audio CASI section—$20

incentive

+ CAPI administration of the

questionnaire (no Audio CASI) at a

neutral site—$40 incentive.

Because of concerns about the

length of the questionnaire, sample

women were administered one of two

sampled versions of the questionnaire.

Also, a few question wording and

question ordering experiments were

embedded in the questionnaire. The

proper version of the questionnaire and

the question wording and ordering

experiments were predetermined and

accessed when the interviewer keyed the

case identification number into her

laptop computer.

The pretest was designed to be

implemented in three pairs of sites. Each

site was all or part of a primary

sampling unit (PSU) of the NHIS. The

sample women were selected from

households that had previously

participated in the NHIS. The selection

of sites was designed to match an urban

area with a suburban or rural area. The

paired sites were New York City with

Nassau/Suffolk Counties, New York;

Dallas with Austin, Texas; and

Greensboro/Winston-Salem with

Hoke/Moore Counties, North Carolina.

A total of 803 sample women 15–44

years of age were selected as shown in

table A. An oversample of 201

non-Hispanic black women were

selected along with 602 sample women

of other races.

Experimental groups were assigned

to NHIS clusters and, therefore, to all

women in a cluster. Consequently, all

women within a cluster were assigned to

the same CAPI, Audio CASI, or neutral

site group; question wording and

ordering experiments were also assigned

by cluster; to avoid any problems or

effects from unequal payment of

incentives to neighbors, the $0 and $20

incentive treatments were assigned by

pretest site.

Interview Mode Effects

One of the major purposes of the

pretest was to determine whether the

complex NSFG questionnaire—one that

made significant use of event histories,

routing patterns, edit checks, and

complex structures such as arrays and

tables—had been converted successfully

to a CAPI format. The number of

problems with the CAPI program was

surprisingly low for such a long and

complex interview (approximately 1,600

uniquely defined questions). The quality

of both the questionnaire and the CAPI

program resulted in very low rates of

missing data, which were defined as

questions with either a ‘‘don’t know’’ or

‘‘refused’’ response.

The pretest was also designed to

test the effect of Audio CASI and

neutral site interviews on the reporting

of sensitive behaviors. Approximately

one-third of the sample women were

interviewed at a neutral site outside of

the sample women’s homes in an

attempt to reduce any discomfort

associated with reporting sensitive

behaviors. Another third of the sample

completed a short Audio CASI interview

that asked about abortion and

contraceptive use after they had

completed the regular CAPI interview in

their homes. The remaining third of the

sample women were interviewed in their

homes with CAPI only.

Both the Audio CASI and the

neutral site interview modes produced a

significant increase in the number of

women who reported ever having had

an abortion compared with the

CAPI-only mode. There was no

significant difference between the Audio

CASI and neutral site modes in either

the proportion of women reporting that

they had ever had an abortion or in the

number of abortions reported.

Incentive Effects

Sample women were assigned to

one of three incentive treatment groups:

no incentive payment, a $20 payment,

or a $40 payment. Women receiving no

incentive and the $20 incentive were

interviewed in their homes; those

interviewed at the neutral site were paid

the $40 incentive to help offset the

additional burden associated with having

Table A. Number of women eligible for the National Survey of Family Growth Pretest, by interview mode and incentive

Interview mode

Incentive

None $20 $40 Total

All CAPI at home1 . . . . . . . . . . . . . . . . . 171 113 – 284

CAPI with Audio CASI2 . . . . . . . . . . . . . . 167 120 – 287

CAPI at a neutral site, $40 incentive . . . . . – – 232 232

Total . . . . . . . . . . . . . . . . . . . . . . . . . 338 233 232 803

– Quantity zero.

1CAPI is Computer-Assisted Personal Interviewing.

2Audio CASI is Audio Computer-Assisted Self-Interviewing.

Page 8 [ Series 1, No. 36
to go to another location for the

interview. Table B provides the response

rates for the pretest by incentive

treatment: the response rates were

59 percent for the no-incentive group

and 67 percent for the $20 and $40

(neutral site) groups.

Main Study Design

Decisions

Based on the results of the pretest,

it was decided that a CAPI

questionnaire, supplemented by an

Audio CASI section (with questions on

abortion and a few other sensitive items)

should be used during the main study.

The Audio CASI technology was shown

during the pretest to be reliable; it was

also accepted well by both interviewers

and respondents, and it apparently

increased abortion reporting. These

findings suggested that Audio CASI was

cost-effective. Using the neutral sites

increased abortion reporting to the same

levels as Audio CASI and also seemed

to improve reporting on other sensitive

items, but it also raised costs

substantially. This increase in cost

appeared to be prohibitive for a

nationwide study.

Paying all respondents a $20 cash

incentive for their participation was also

recommended. The pretest results

showed that the incentive actually paid

for itself, because it raised the response

rate and saved interviewers time and

travel costs. The incentive also increased

abortion reporting. In addition, it

seemed justified by the burden placed

on respondents by the length,

complexity, and sensitivity of the Cycle

5 questionnaire.

Sample Design

Overview

This section describes how the

NSFG main study sample was

designed and selected. The NSFG

sample was drawn from the 1993

National Health Interview Survey

(NHIS), so this section begins with a

brief summary of the NHIS sample

design and then describes the NSFG

Table B. Response rates for the Pretest, by amount of incentive

Status

Amount of incentive

None $20 $40 Total

Number Percent Number Percent Number Percent Number Percent

A Total cases assigned . . . . . . . . . . . . . . . . . . . . . . . 338 100.0 233 100.0 232 100.0 803 100.0

B Ineligible cases

1 SW not 15–44 years* . . . . . . . . . . . . . . . . . . . . 1 0.3 1 0.4 2 0.9 4 0.5

2 SW not female . . . . . . . . . . . . . . . . . . . . . . . . 1 0.3 – 0.0 – 0.0 1 0.1

3 SW out of country . . . . . . . . . . . . . . . . . . . . . . 2 0.6 4 1.7 2 0.9 8 1.0

4 SW deceased . . . . . . . . . . . . . . . . . . . . . . . . . 1 0.3 1 0.4 1 0.4 3 0.4

5 Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.5 6 2.5 5 2.2 16 2.0

C Total eligible cases . . . . . . . . . . . . . . . . . . . . . . . . 333 100.0 227 100.0 227 100.0 787 100.0

D Cases completed

1 Interview completed . . . . . . . . . . . . . . . . . . . . . 196 58.9 153 67.4 151 66.5 500 63.5

2 SW untraceable . . . . . . . . . . . . . . . . . . . . . . . . 6 1.8 7 3.1 7 3.1 20 2.6

3 SW moved . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 8.7 10 4.4 13 5.7 52 6.6

4 SW final refusal . . . . . . . . . . . . . . . . . . . . . . . . 48 14.4 23 10.1 21 9.3 92 11.7

5 Breakoff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.0 – 0.0 – 0.0 – 0.0

6 Parental consent refused . . . . . . . . . . . . . . . . . . 4 1.2 – 0.0 3 1.3 7 0.9

7 Parental consent unattainable . . . . . . . . . . . . . . . – 0.0 – 0.0 – 0.0 – 0.0

8 SW unavailable . . . . . . . . . . . . . . . . . . . . . . . . 19 5.7 10 4.4 13 5.7 42 5.3

9 SW unlocatable . . . . . . . . . . . . . . . . . . . . . . . . 23 6.9 14 6.2 13 5.7 50 6.4

10 SW physically/mentally incapable . . . . . . . . . . . . . 1 0.3 2 0.9 – 0.0 3 0.4

11 SW language problem, Spanish . . . . . . . . . . . . . . 6 1.8 5 2.2 5 2.2 16 2.0

12 SW language problem, other . . . . . . . . . . . . . . . . 1 0.3 3 1.3 1 0.5 5 0.6

13 Other noninterview . . . . . . . . . . . . . . . . . . . . . . – 0.0 – 0.0 – 0.0 – 0.0

14 Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333 100.0 227 100.0 227 100.0 787 100.0

E Unadjusted response rate** . . . . . . . . . . . . . . . . . . ... 58.9 . . . 67.4 . . . 66.5 . . . 63.5

F Adjusted response rate*** . . . . . . . . . . . . . . . . . . . . ... 65.8 . . . 72.2 . . . 72.2 . . . 69.5

. . . Category not applicable.

– Quantity zero.

0.0 Quantity more than zero but less than 0.05.

*SW = Sample woman.

**The unadjusted response rate is calculated by dividing the total number of completed interviews by the total number of eligible cases.

***The adjusted response rate is calculated by dividing the total number of completed interviews by the total number of eligible cases less the sample women who had moved more than 120 miles from

any pretest primary sampling unit and the sample women who spoke only Spanish. Because of the limited number of pretest primary sampling units and the lack of a Spanish questionnaire in the

Pretest, cases in these two categories had no opportunity to be interviewed.

NOTE: Final pretest data collection status report, 1995 National Survey of Family Growth-Pretest.

Series 1, No. 36 [ Page 9
sampling procedures. It concludes with a

summary of sample sizes, response

rates, and design effects. (For more

details on the topics covered in this

section, and a discussion of imputation

and variance estimation, see reference

16.)

For Cycle 5 of the NSFG, a

national probability sample of 14,000

women 15–44 years of age was selected

from among households that responded

to the 1993 NHIS. The NHIS is a

continuous multistage household survey

conducted by NCHS that covers the

U.S. civilian noninstitutionalized

population. Data are collected for each

household member on health conditions,

doctor visits, hospitalizations,

disabilities, and other health-related

topics, as well as demographic and

economic data for the household and

household members. In 1993, the NHIS

was conducted in 198 PSU’s, where a

PSU is a county or group of adjacent

counties. PSU’s were located in nearly

every State and included all of the

largest metropolitan areas in the United

States.

NCHS provided RTI with data files

containing household-level and

person-level data for all persons in

households responding to the 1993

NHIS. To obtain a sufficient number of

black and Hispanic women for the

NSFG from the NHIS sample, all

households with black and Hispanic

women in the 1993 NHIS had to be

included in the NSFG. This required the

NSFG to interview in all 198 NHIS

PSU’s. About 43 percent of the ‘‘white

and other’’ women from the NHIS were

selected for the NSFG sample. Thus,

black and Hispanic women were

sampled at a higher rate than other

women for the NSFG.

Sampled women who had moved

since the NHIS interview were traced to

their new address, and an interviewer

conducted the interview at the new

address. Because of the stratification and

unequal sampling rates, sampling

weights must be used to calculate

accurate numbers, percents, and other

statistics or to compute accurate

sampling errors. The weights adjust for:

1. the different sampling rates for

Hispanic, black, and other women;

2. for nonresponse; and

3. for undercoverage by age, race, and

parity. See reference 16 for more

discussion of weights and their

effects on analysis.

Design of the National

Health Interview Survey

The National Health Interview

Survey (NHIS) is a stratified multistage

household survey that covers the civilian

noninstitutionalized population of the

United States. The NHIS design is

revised each decade using data from the

most recent census. Cycle 5 of the

NSFG used the NHIS sample based on

the design developed for the period

1985 to 1994. A complete description of

the NHIS design is given in reference

16.

For the NHIS, the geographic area

of the United States was divided into

about 1,900 areas called primary

sampling units (PSU’s). A PSU consists

of an individual county, a small group

of contiguous counties, or a

metropolitan statistical area (MSA). The

1,900 PSU’s were stratified using

socioeconomic and demographic

variables. The sample was selected with

probability proportional to the

population size (pps) within a stratum.

The 1985–94 NHIS sample contained

198 PSU’s. Under the pps design, the

52 largest PSU’S are all selected into

the sample. These PSU’S are called

self-representing PSU’S. The remainder

of the PSU’S were grouped into 73

strata, and two PSU’S were selected

from each stratum. That is, the final

NHIS sample of 198 PSU’S consists of

52 self-representing PSU’S and 146

nonself-representing PSU’S.

Each PSU was divided into

geographically defined ‘‘area segments.’’

Area segments with a higher proportion

of black persons formed a stratum that

was sampled at a higher rate than the

other area segments in the PSU. These

strata were called ‘‘area

segments—oversampled for blacks’’ and

‘‘area segments—not oversampled for

blacks,’’ respectively.

In addition to the area frame, a

separate new-construction frame was

used in most PSU’S. The

new-construction frame consisted of

housing units constructed after the 1980

Census. Building permits provided the

source information for constructing this

frame. These segments formed a third

sampling stratum, called the ‘‘permit’’

stratum. An NHIS PSU may contain a

sample of segments from all three strata,

from two of the three strata, or from

only one stratum.

Within each stratum, sample area

segments were selected systematically,

and then clusters of housing units were

selected within the sample segments.

The clusters were spread over a small

geographical area (that is, they were

‘‘noncompact clusters’’), and the

expected cluster size was eight housing

units. NCHS selected a systematic

sample of building permit segments.

The NHIS sample is divided into 51

(or sometimes 52) weekly interviewer

assignment samples; each weekly

sample represents a national probability

sample of housing units. NCHS can then

form national samples by combining

weekly samples.

In 1993, budget restrictions required

NCHS to field only 7 of the 13 weekly

samples in the second quarter

(April–June), so the 1993 NHIS sample

contained 46 weekly samples (that is, 6

of the 52 weekly samples were

dropped). The 1993 NHIS respondent

sample included data for 109,671

persons in 43,007 households. In

addition, the households interviewed

during the first two quarters of the 1993

NHIS were administered only the core

NHIS questionnaire.

National Survey of Family

Growth Sampling Design

The NSFG sample design required

at least 10,500 completed interviews.

Assuming an 80 percent response rate,

13,125 women would need to be

selected. Assuming a 75 percent rate,

14,000 would need to be selected. Only

one woman per household was selected.

All households containing Hispanic or

non-Hispanic black women were

included in the NSFG, but not all

households of mixed or other race were

included. Because the design required

the selection of all households

Page 10 [ Series 1, No. 36
containing Hispanic and non-Hispanic

black women, the probability sampling

design consisted mainly of selecting the

remainder of the sample of households

(and women) among the PSU’S and

selecting the households within each

PSU. The subsample of households was

selected with probability proportional to

the number of women in the household

so that each sampled woman would

have an equal probability of selection

(and equal weight) for the NSFG.

The 1993 NHIS consisted of 46

weekly samples. The 1995 NSFG

sampling frame included 25,534 women

15–44 years of age in 21,168

households (1.21 women per

household). The ages are based on the

estimated midpoint of the NSFG data

collection period (April 1, 1995), so a

woman was included in the NSFG

sampling frame if she was born between

April 1, 1950, and March 31, 1980,

inclusive.

The sampling frame contained

2,684 Hispanic women, 4,042

non-Hispanic black women, and 18,808

women of other races/ethnicities (called

‘‘other women’’). A total of 2,135

households contained one or more

Hispanic women (called a Hispanic

household); 3,206 contained one or

more non-Hispanic black women, but no

Hispanic women (called a non-Hispanic

black household); and 15,827 contained

only women of other race/ethnicities

(called ‘‘other households’’).

The sample design requirements

specified that the sampling variance for

weighted estimates should be

minimized, and the NSFG was to be

linked to the NHIS. These requirements

constrained the NSFG sample design.

The design effect is the increase (or

decrease) in the sampling variance

attributable to the sampling design

compared with the sampling variance of

a simple random sample of the same

size from the same population. The

stratification, clustering, and

disproportionate sampling in the NHIS

mean that the NSFG will have larger

sampling errors than a simple random

sample. Also, the NSFG’s higher

sampling rates for Hispanic and

non-Hispanic black women contribute to

the total NSFG design effect.

Table C displays design effects and

sample sizes for all women and black

women by cycle. The nominal sample

size is the actual number of women who

were interviewed. It is labeled the

‘‘nominal’’ sample size because a

statistic based upon this many

interviews from a complex survey has a

larger sampling error than a statistic

from a simple random sample and the

same number of interviews. The

effective sample size is the nominal

sample size divided by the design

effect—the sample size for a simple

random sample with the same precision.

Table C shows that the design effect for

Cycle 5 of the NSFG (1.46) is less than

one-half the design effect for Cycle 3

(3.00). The effective sample size for

Cycle 5 (7,429) is 2.8 times the effective

sample size in Cycle 3 and 1.4 times the

effective sample size in Cycle 4 (5,382).

Thus, Cycle 5 data have smaller

sampling errors than those of Cycle 4,

and much smaller sampling errors than

Cycle 3.

Sampling Procedure and

Allocations

The NHIS sampling frame was

divided into parts, or strata, based on

the characteristics of the households in

the NHIS clusters. (An NHIS cluster is

a portion of an area segment or a permit

segment.) These strata are

+ 1,015 clusters containing only

Hispanic or non-Hispanic black

households (called the minority

stratum)

+ 1,518 clusters containing Hispanic

or non-Hispanic black households

and other households (called the

mixed stratum)

+ 2,250 clusters containing three or

more other households (called the

high-density stratum)

+ 2,160 clusters containing only one

or two other households (called the

low-density stratum)

See table D for the number and

classification of NHIS households in

these strata.

The sampling design for Cycle 5

specified that all NHIS households with

Hispanic or non-Hispanic black women

were to be selected with certainty (that

is, included in the sample). Therefore,

field interviewers went to all NHIS

clusters in the minority stratum and the

mixed stratum. For the other

households, less than one-half of the

households were selected. One

household was expected to be selected

from clusters in the high-density

stratum. For the low-density stratum,

approximately one-half of the clusters

would be selected and approximately

one household would be selected in the

cluster.

As a source of potential cost

reduction in data collection, the

households in the low-density stratum

were undersampled to reduce the

number of NHIS clusters with only one

household. The households in the mixed

stratum and the high-density stratum

were oversampled by 10 percent. This

design results in only a slight increase

(less than 5 percent) in the design effect

attributable to unequal weighting; the

cost-reduction effect was considered to

be more important.

In order to compute unbiased

variance estimates, sampling theory

Table C. Estimated design effects and sample sizes for National Survey of Family Growth Cycles 3, 4, and 5

Size and effect

Cycle 3 (1982) Cycle 4 (1988) Cycle 5 (1995)

Total Black Total Black Total Black

Nominal sample size ........ 7,969 3,201 8,450 2,811 10,847 2,511

Effective sample size ........ 2,656 1,131 5,382 1,479 7,429 1,504

Design effect ............. 3.00 2.83 1.57 1.90 1.46 1.67

NOTE: For definitions of terms, see text and appendix I.

Series 1, No. 36 [ Page 11
requires that the households, and the

woman in each household, be selected

independently in each PSU. This

allocation was done in three steps. First,

the number of eligible noncertainty

households in each PSU was reviewed

to ensure that each PSU would have

some respondents; 16 noncertainty

households in 3 small PSU’s were

selected with certainty. Second, only one

woman could be selected in each

household; 1,480 households were

included with certainty because they had

more than one eligible woman. Third,

the remaining sample cases (7,163

women) not selected with certainty were

allocated to the PSU’s based on the

weighted count of women in each PSU

in the three cluster strata (minority,

mixed, and nonminority).

For the sample selection of

households within each PSU, Chromy’s

procedure (17) was used with the

weighted number of women in a

household as the size measure. The

sampling frame in each PSU was

stratified by the cluster type (mixed and

high-density clusters and low-density

clusters). The sampling frame within

each stratum was then ordered using the

NHIS cluster and metropolitan status (in

a MSA, central city; in a MSA, not in

the central city; and not in a MSA,

where MSA is a Metropolitan Statistical

Area) and the NHIS cluster. After the

household was selected, one woman was

randomly selected from each household.

Initially, a sample of 14,000 women

was selected and a random subsample of

875 women was set aside as a reserve

sample. Because of the high number of

cases that could not be located, NCHS

decided to field the full sample of

14,000 sampled women.

Sample Sizes, Selection

Probabilities, and Response

Rates

Table E shows the number of cases

selected from the 1993 NHIS and the

average selection probability, average

weight, and the relative variance of the

sampling weights. The average selection

probabilities for Hispanic and

non-Hispanic black women are much

higher than for the other race/ethnicity

group because of the oversampling of

Hispanic and black women. In addition,

the NSFG requirement to select only

one woman per household resulted in

lower selection probabilities (and larger

full-sample sampling weights) for

women in larger households than for

women in smaller households. This

occurred almost exclusively in the

households with Hispanic or

non-Hispanic black women, because all

Table D. Distribution of National Health Interview Survey clusters and households, by cluster composition strata

Composition strata

NHIS

clusters1

Households

Total Minority Other

Households

per cluster

Total .................... 6,943 21,168 5,341 15,827 3.05

Minority only ............... 1,015 2,920 2,920 – 2.88

Mixed ................... 1,518 5,844 2,421 3,423 3.85

Nonminority only ............. 4,410 12,404 – 12,404 2.81

High density ............... 2,250 9,114 – 9,114 4.05

Low density ................ 2,160 3,290 – 3,290 1.52

– Quantity zero.

1NHIS is National Health Interview Survey.

Table E. Sample size, probability of selection, average weight, and relative variance of weights, by race/ethnicity and number of eligible

women: 1995 National Survey of Family Growth

Race/ethnicity and number of eligible women

Sample

size

Average

probability of

selection

Average

weight1

Relative

variance

All women 15–44 years of age .............. 14,000 0.00026124 3,828 0.20

Race/ethnicity2

Hispanic ............................ 2,097 0.00036788 2,718 0.30

Non-Hispanic black ..................... 3,205 0.00046559 2,148 0.41

Other .............................. 8,698 0.00021211 4,715 0.06

Number of eligible women in household

1 ................................ 10,546 0.00028619 3,494 0.20

2 ................................ 2,841 0.00022330 4,478 0.11

3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 526 0.00015977 6,259 0.08

4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 0.00012545 7,971 0.07

5 or more . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 0.00009648 10,365 0.14

1The weight is the sampling weight before any nonresponse or poststratification adjustments.

2Race/ethnicity based on data from the National Health Interview Survey.

Page 12 [ Series 1, No. 36
of these households were selected into

the sample with certainty. The

race/ethnicity classification in table E is

based on the NHIS-reported data, which

were subject to revision in the NSFG

interview.

The number of completed

interviews and the location and response

rates are shown in table F. The location

rates are based on the total number of

cases in the sample (14,000 in total). Of

the 14,000 sampled cases, 13,243 cases

(94.6 percent) were located. Of the

13,795 eligible women, 10,847 were

interviewed (78.6 percent). In the

race/ethnicity groups in table F, all three

populations had approximately the same

overall response rates. For the black and

Hispanic women, the location rates were

lower (about 92 percent) than for white

and other women (96 percent). This

difference in location rates was offset by

higher response rates among black and

Hispanic women who were located.

Sampled women under 24 years of age

had the highest overall response rates

(about 82 percent), and women 25–29

years old had the lowest overall

response rate (74.5 percent). Sampled

women 25–29 years of age had both the

lowest location rate (91.7 percent) and

the lowest response rate among located

cases. Race/ethnicity and age are based

on NHIS data in table F.

Table G shows clustering and the

variation in the weights among

completed interviews. The number of

clusters with one or more completed

interviews was 5,377, 71 percent more

than the 3,143 used in Cycle 4. The

average number of completed interviews

per cluster was 2.01 compared with 2.69

in Cycle 4 (18). In other words, the

Cycle 5 sample was considerably more

dispersed than the Cycle 4 sample. This

dispersion probably increased data

collection costs, but reduced variances.

Tracing

Introduction

Akey feature of Cycle 5 was the

linkage of the NSFG sample to

the NHIS. Many large surveys

are done with area frame samples that

require listing and screening the housing

Table F. Response rates for Cycle 5 of the National Survey of Family Growth among completed cases in the National Health Interview

Survey, by race/ethnicity and age: 1995 National Survey of Family Growth

Race/ethnicity and age

Sample

sizes

Located

cases

Location

rate

Eligible

women1

Completed

interviews

Response

rate

All women 15–44 years ............. 14,000 13,243 94.6 13,795 10,847 78.6

Race/ethnicity

Hispanic ....................... 2,097 1,926 91.8 2,030 1,613 79.5

Non-Hispanic .................... 3,205 2,939 91.7 3,169 2,464 77.8

Other ......................... 8,698 8,378 96.3 8,596 6,770 78.8

Age (April 1, 1995)

15–17 years .................... 1,040 1,001 96.3 1,020 841 82.5

18–24 years .................... 2,622 2,452 93.5 2,586 2,122 82.1

25–29 years .................... 2,339 2,146 91.7 2,310 1,722 74.5

30–34 years .................... 2,815 2,656 94.4 2,783 2,172 78.0

35–39 years .................... 2,751 2,632 95.7 2,723 2,127 78.1

40–44 years .................... 2,433 2,356 96.8 2,373 1,863 78.5

1Unlocatables were assumed to be eligible.

NOTE: Race/ethnicity and age are based on data from the National Health Interview Survey.

Table G. Clustering and weight variation for completed interviews by race/ethnicity and age: 1995 National Survey of Family Growth Cycle 5

Race/ethnicity and age1

Completed

interviews

Number of

clusters with 1

or more

completes

Average

number of completes

per cluster

All women 15–44 years of age ......... 10,847 5,377 2.01

Race/ethnicity

Hispanic ....................... 1,553 1,020 1.52

Non-Hispanic black ................ 2,446 1,316 1.86

Other ......................... 6,848 4,064 1.69

Age (April 1, 1995)

15–17 years . . . . . . . . . . . . . . . . . . . . 828 786 1.05

18–24 years .................... 2,106 1,800 1.17

25–29 years .................... 1,716 1,473 1.16

30–34 years .................... 2,165 1,875 1.15

35–39 years .................... 2,125 1,814 1.17

40–44 years .................... 1,907 1,655 1.15

1Race/ethnicity and age based on the National Survey of Family Growth interview.

Series 1, No. 36 [ Page 13
units in an area to identify people who

will be in the sample. In contrast, Cycle

5 of the NSFG was based on a list

sample—a list of women in households

interviewed in the NHIS in 1993. If

those women moved between the time

of the NHIS interview in 1993 and their

NSFG interview in 1995, an effort was

made to locate them at their new

address to ask them for an NSFG

interview. In other words, tracing for the

Cycle 5 main study was simply an effort

to find the current address and telephone

number for a woman in the sample so

that she could be asked for an interview.

No other information about her was

sought except in the interview itself.

The tracing effort depended primarily

on three factors that made tracing more

difficult for the NSFG sample than it would

be for some other studies:

1. The sample list was almost 2 years

old by the time the NSFG interview

was done.

2. Some of the information needed to

locate movers was missing in about

one-third of all cases.

3. More than one in five women 15–44

years of age move every year—some

more than once—and some also

changed their names. For example,

22 percent of persons 15–44 years of

age move each year (19).

Despite these difficulties, considerable

success was obtained using the

procedures described.

Tracing of Sampled

Women

Pretest—Before the NSFG main study

data collection effort, a multistage tracing

process was designed and implemented to

confirm the address of each sample

woman. This process was developed in

response to the higher-than-expected

percentage (9 percent) of sample women

who could not be located in the NSFG

pretest in 1993. The 9 percent nonlocation

rate occurred because the pretest sample

addresses were 2 years old, the U.S. Postal

Service National Change of Address

(NCOA) records identified fewer movers

than expected, too much time lapsed

between tracing and pretest data collection,

and the short pretest data collection period

did not allow enough time for a complete

tracing effort. The age of the NHIS locator

information was the most important of

these problems. Most of the address

information provided for the pretest was

over 2 years old, with some as old as 28

months.

Main study—The main study

sample was selected from all of the

1993 NHIS—that is, January–December

1993. When interviewing began in

January 1995, the NHIS addresses were

13–24 months old. To obtain more

recent addresses for the sampled women

before data collection, these advance

tracing steps were implemented:

+ the addresses were submitted to the

U.S. Postal Service’s NCOA system

+ the telephone numbers were

submitted to a telephone look-up

service called Telematch

+ the RTI Telephone Survey Unit

called each phone number to verify

it

+ a small percentage who could not be

located were submitted to a tracing

contractor

+ the addresses were submitted again

to NCOA before mailing the

advance letter

+ a final postcard mailing was done to

identify undeliverable addresses and

request change of address

information.

These steps as well as field tracing steps

are outlined, and, to the extent possible,

the results are summarized in table H.

The following information from the

NHIS was used in tracing:

+ sample woman’s name, address,

telephone number, Social Security

number, date of birth, race, and

marital status

+ NHIS reference person’s (head of

household) name, address, telephone

number, Social Security number, and

relationship to sample woman

+ NHIS contact person’s name,

address, telephone number, and

relationship to sample woman

+ whether the sample woman was the

NHIS respondent

+ date of NHIS interview.

These items are referred to as ‘‘locator

information’’ in this report.

Table H. Tracing steps in the 1995 National Survey of Family Growth

Step Date

Number

of cases

sent

Number

of cases

updated/

located

1. NCOA submission1 ................... 07/01/94 33,521 5,537

2. Mailing to postmasters for Rural

Route addresses ..................... 07/22/94 2

NA NA

3. Telematch submission ................. 07/22/94 3

32,876 4,608

4. Telephone tracing .................... 8/1/94–10/31/94 14,000 11,787

5. Tracing contractor submission ............. 8/29/94–11/21/94 1,599 863

6. NCOA resubmission ................... 12/01/94 3

33,704 1,287

7. Postcard mailing ..................... 12/19/94 14,000 NA

8. Field tracing by field interviewers ........... 1/14/95–10/31/95 14,000 13,273

9. DMV requests4 ...................... 1/14/95–10/31/95 952 545

10. Database searches ................... 1/14/95–10/31/95 2,459 1,512

11. U.S. Bureau of the Census tracing .......... 8/1/95–9/30/95 641 149

1NCOA is National Change of Address.

2NA is not ascertained.

3Includes reference persons (head of household) and contact persons given in NHIS interview.

4DMV is the Department of Motor Vehicles.

Page 14 [ Series 1, No. 36
Completeness of Locator

Information

The planning and preparation for

the advance tracing operation assumed

that the locator information from the

NHIS would be nearly complete.

However, about one-third of the 14,000

cases selected for the NSFG had

missing locator information. As shown

in table J, the NHIS file had 320 sample

women with missing or invalid names

(for example, Jane Doe, Mrs. Refused,

Person 1, etc.); 217 women for whom

the name of the ‘‘reference person’’ was

missing; for 412 women (3 percent), no

date of birth was recorded; 3,455 sample

women (25 percent) had no contact

person identified; and 4,329 (31 percent)

had no Social Security number recorded.

These missing data made tracing more

difficult and more costly. Clearly, it is

difficult to locate a woman if her name

is unknown, even if her age, race, and

former address are known. The lack of a

contact person greatly reduces the

chance of locating the woman’s address

if she moves. A missing Social Security

number makes it impossible to do large

database searches, which is the most

economical and most effective way to

update addresses and telephone

numbers.

Results of Advance Tracing

Table K shows the overall results of

the advance tracing operation. At the

end of these activities—NCOA,

Telematch, telephone tracing, and

contractor tracing—addresses and/or

telephone numbers had been confirmed

for 12,650 sample women (90 percent).

An additional 87 sample women were

located (1 percent) but refused to

participate in the telephone tracing

confirmation process. These procedures

did not locate 977 sample women

(7 percent) before the start of data

collection. Another 210 sample women

(2 percent) were located, but could not

be contacted to confirm the address.

Field Tracing

The advance tracing procedures

were designed to provide the field

interviewers with a current address and

telephone number for each sample

woman. When data collection began in

January 1995, 977 sample women

(7 percent of the entire sample) had not

yet been located or confirmed. All of

these cases were assigned to the field

for in-person followup, although they

were not worked immediately by the

interviewer. Instead, initial data

collection efforts focused on sample

women who had been located during

advance tracing.

If, during her initial contact, an

interviewer found that the sample

woman had moved, she assigned a

pending tracing code to the case and

began tracing. At the start of data

collection, interviewers were instructed

to follow these tracing steps:

+ ask the current resident or neighbors

if they have an address or phone

number for the sample woman

+ submit an Address Information

Request Form to the area postmaster

+ call directory assistance and ask for

the sample woman’s phone number

+ call the NHIS contact person listed

on the Case Assignment Folder

(CAF) to ask for an address or

phone number.

Interviewers wrote down the efforts they

made to locate the woman’s address on

the CAF.

Early in the data collection period,

two main types of tracing problems

were discovered. First, some addresses

that had been confirmed or obtained

during the advance tracing operation

were already out of date. Second,

interviewers had particular difficulty

locating sample women with incomplete

contact information from the NHIS,

such as missing or partial names,

missing or partial addresses, missing

contact persons, and imputed birthdates.

A profile of cases requiring field tracing

indicated that black and Hispanic

women, those with lower family

incomes, and those with incomplete

tracing information were more difficult

to locate. The profile in table L shows

that 3.8 percent of those with complete

locator information (that is, complete

sample woman name, Social Security

number, and contact person name) could

not be located, compared with

8.6 percent of those with incomplete

locator information. This differential was

found among Hispanic, white, and black

women, and also among both low- and

high-income women.

In response to these tracing

difficulties, several decisions were made

to improve success in locating sample

Table J. Summary of missing locator information from the National Health Interview Survey

in the sample for the 1995 National Survey of Family Growth

Problems with NHIS data1 Number Percent

Total number of cases ..................... 14,000 100

Sample woman’s name was missing or invalid . . . . . . 320 2

Reference person’s name missing . . . . . . . . . . . . . . 217 2

Date of birth imputed . . . . . . . . . . . . . . . . . . . . . . 412 3

No contact person listed .................... 3,455 25

Social Security number missing ............... 4,329 31

1NHIS is National Health Interview Survey.

Table K. Final results of advance tracing operation: August–November, 1994

Result Number Percent

Located .............................. 12,650 90

Unable to locate ......................... 1

977 7

Located, refused . . . . . . . . . . . . . . . . . . . . . . . . . 87 1

Unable to contact . . . . . . . . . . . . . . . . . . . . . . . . 210 2

Ineligible . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 –

Deceased ............................. 6 –

Language barrier ........................ 4 –

Total sample ........................... 14,000 100

– Quantity zero.

1Includes 736 women not located by the tracing contractor, and 241 women not located by telephone tracing because their names

were not listed or were imcomplete.

Series 1, No. 36 [ Page 15
women and ensure that the required

10,500 interviews would be completed.

First, the reserve sample of 875

eligible women was released and data

collection was extended from mid-June

through the end of July. Second, a

sample of unlocatable cases was

reviewed by a tracing expert to identify

additional steps that could be taken to

find the sample women. As a result of

this review, the field staff were given

additional ideas for locating sample

women, and in some instances, cases

were returned to interviewers for

additional contact attempts. Third, a

series of conference calls with all of the

field supervisors was held to address the

tracing problems and to discuss ways to

improve the location rate. Supervisors

were asked to hold similar calls with

their interviewers to discuss these issues.

Fourth, memoranda were mailed to the

field staff to offer suggestions for tracing

sample women, and interviewers were

encouraged to report techniques they

had found to be especially effective in

locating the sample women or producing

new tracing leads.

Central Office Tracing

Several central office tracing steps

were implemented to help field

interviewers locate sample women.

These included Department of Motor

Vehicles (DMV) record checks for all

tracing cases and TransUnion interactive

database searches.

To conduct the DMV record

searches, lists of all tracing cases were

first generated from the control system

and sorted by State. The lists were then

mailed to the appropriate State DMV

office, along with a letter from NCHS

explaining the purpose of the request.

Replies from the DMV’s were generally

received within 2 weeks of the request.

As shown in table M, a total of 952

addresses were requested from 40 State

DMV offices. Addresses were returned

for 545 cases, for a return rate of

57 percent. The DMV’s indicated the

last known address for the sample

women, based on their driver’s licenses.

However, for an unknown percentage of

these cases, the address returned by

DMV was the same as the one already

on file. The addresses were mailed to

the field staff for in-person followup of

new or different addresses.

As shown in table M, addresses

were obtained for 1,058 of 1,259 sample

women, for a return rate of 84 percent

when the interviewer had the Social

Security number compared with

38 percent when they did not. This

success rate demonstrates the

importance of having the Social Security

number as a tracing tool. As with the

DMV records, however, an unknown

percentage of the addresses and

telephone numbers obtained through

these searches matched those already on

file for the sample woman.

Using names and addresses as the

search criteria, records for 454 of 1,200

sample women were obtained, for a

return rate of only 38 percent (table M).

The names and addresses of sample

women were used to access crisscross

directories and other TransUnion

databases when:

Table L. Percent not located in the 1995 National Survey of Family Growth, by completeness of locator information and selected

characteristics

Characteristic

Number in the sample Percent not located

Total Complete Incomplete Total Complete Incomplete

All women ...................... 14,000 9,306 4,694 5.4 3.8 8.6

Race/ethnicity

Hispanic ....................... 2,097 1,259 838 8.2 5.9 11.6

Non-Hispanic Black ................ 3,205 2,038 1,167 8.3 6.2 12.0

Non-Hispanic Other ................ 8,698 6,009 2,689 3.7 2.6 6.1

Family income

Under $20,000 ................... 3,954 2,872 1,082 8.9 7.2 13.5

$20,000 or more .................. 7,916 5,539 2,377 2.5 1.9 3.9

Not reported .................... 2,130 895 1,235 9.8 5.0 13.3

NOTE: ‘‘Complete’’ locator information means that the NSFG sampled woman’s name, Social Security number, and contact person are all known. ‘‘Incomplete’’ means that one or more of these items

was/were missing.

Table M. Results of central office tracing efforts: 1995 National Survey of Family Growth

Central office tracing activity Number Percent

DMV record searches

Records found . . . . . . . . . . . . . . . . . . . . . . . . . . 545 57

Records not found . . . . . . . . . . . . . . . . . . . . . . . 407 43

Total records requested . . . . . . . . . . . . . . . . . . . . 952 100

TransUnion database searches with SSN1

Address/phone returned .................... 1,058 84

No address/phone returned . . . . . . . . . . . . . . . . . . 201 16

Total records searched ..................... 1,259 100

TransUnion address database searches without SSN

Address/phone returned . . . . . . . . . . . . . . . . . . . . 454 38

No address/phone returned . . . . . . . . . . . . . . . . . . 746 62

Total records searched ..................... 1,200 100

1SSN is Social Security number.

Page 16 [ Series 1, No. 36
1. the sample woman’s Social Security

number was missing from the NHIS

file;

2. no new information was found

through the credit database search;

or

3. the address returned through the

credit database was not successful in

locating the sample woman.

U.S. Bureau of the Census

Tracing

As another means of locating the

sample women, an agreement was

reached with the U.S. Bureau of the

Census to trace some remaining

unlocated women. Bureau of the Census

interviewers had conducted the original

NHIS interviews with the sampled

households. To allow time for the

Census Bureau’s 12 Regional Offices to

do the tracing, data collection was

extended an additional 3 months,

through October 1995.

In early August 1995, all

unlocatable cases were retrieved from

the NSFG field interviewers, reviewed

by the project staff, and forwarded to

the appropriate U.S. Bureau of the

Census Regional Office. The Regional

Offices were asked to complete their

tracing activities by the end of

September. The tracing activities

undertaken varied by Regional Office

but included field tracing by Bureau of

the Census interviewers, DMV record

searches, and phone disk searches.

As shown in table N, the Bureau of

the Census traced a total of 641 sample

women. They reported the following

results: 149 sample women located

(23 percent), 329 sample women not

located (51 percent), 16 new leads from

DMV record searches (3 percent), 108

new leads from phone disc searches

(17 percent), 31 new leads for reference

persons, contact persons, or other

locating sources (5 percent), and 8

refusals (1 percent). In many cases, the

‘‘new lead’’ was an address, phone

number, or contact person that had

previously been obtained through other

sources, but had not led to the sample

woman.

Cases with ‘‘new leads’’ were

returned to the field interviewers for

followup as they became available. All

new addresses and telephone numbers

were attempted. Using the information

leads provided by the U.S. Bureau of

the Census, the field interviewers

located and interviewed 69 sample

women (11 percent of the 641 sent to

the Bureau); 5 sample women

(1 percent) were located and found to be

ineligible; 42 (7 percent) were located

but refused to participate in the survey;

the 27 remaining located women did not

participate for some other reason

(unavailable during survey period,

language barrier, etc.). The Bureau of

the Census could not locate 498 of the

sample women traced (78 percent),

including 171 for which the Census

Bureau provided a new address, phone

number, or contact person.

Table H, shown earlier, summarized

the 11 steps in the entire tracing

process. Steps 1–7, which were done

before fieldwork began, were called

‘‘Advance tracing.’’ Steps 8–11 were

called ‘‘Field and Central Office

tracing,’’ which refers to tracing steps

taken after NSFG interviewing began in

January 1995. Table O presents the final

results of the combined field and central

office tracing operation for the NSFG

main study. Of the 3,605 sample women

who were traced at some point during

the field period, 2,153 (60 percent) were

located and interviewed; 56 (2 percent)

were located and found to be ineligible;

439 (12 percent) were located and

refused to participate in the survey; 230

(6 percent) were located but did not

participate for some other reason

(unavailable during survey period,

language barrier, etc.), and 727

(20 percent) could not be located.

Table N. Results of U.S. Bureau of the Census tracing, by final field interview status

Census result

Final RTI field interview status

Interview

complete

Final unable

to locate

Final other

noninterview1

Total

number

Total2

percent

Number

Sample woman located . . . . . . . . . . . . . . . . . . 49 56 44 149 24

Unable to locate sample woman . . . . . . . . . . . . . 2 327 – 329 51

New lead from DMV3 . . . . . . . . . . . . . . . . . . . . – 14 2 16 2

New lead from phone disk searches . . . . . . . . . . 14 75 19 105 17

New lead for reference, contact, or other person . . . 4 22 5 31 5

Refusal ............................ – 4 4 8 1

Total cases traced by Census . . . . . . . . . . . . . . 69 498 74 641 100

– Quantity zero.

1Includes cases with these final dispositions: sample woman moved outside of geographic range, final unavailable, language barrier, other noninterview, final ineligible, and final refusal.

2Percentages may not add due to rounding.

3DMV is Department of Motor Vehicles.

Table O. Final results of field tracing: 1995 National Survey of Family Growth

Final result Number Percent

Located, interviewed .................... 2,153 60

Located, ineligible . . . . . . . . . . . . . . . . . . . . . . 56 2

Located, refused . . . . . . . . . . . . . . . . . . . . . . . 439 12

Located, other final noninterview . . . . . . . . . . . . . 230 6

Unable to locate . . . . . . . . . . . . . . . . . . . . . . . 727 20

Total sample members traced in field .......... 3,605 100

Series 1, No. 36 [ Page 17
After all advance tracing and field

tracing activities, 727 women could not

be located (5 percent); 13,273 women

were located, for a final location rate of

95 percent.

Summary

NSFG sample sizes are shown in

table P. In summary, we began with

14,000 sample cases; 205 of those were

determined to be ineligible, leaving

13,795 eligible women. A total of

13,243 were located (‘‘traced’’)

(94.5 percent unweighted), including

13,038 who were located and eligible.

Of the 13,038 located and eligible,

10,847 were interviewed. The

unweighted response rate for the 13,795

eligible women was 78.6 percent. The

comparable unweighted response rate

was 76.5 percent for Hispanic women,

80.2 percent for white women,

77.2 percent for black women, and

71.3 percent for non-Hispanic women of

other races. Further data on screening,

tracing, and response rates are shown in

detailed table 1 of reference 16.

Questionnaire

Development

Overview

This section describes the

questionnaire development,

programming, and testing

operations for the main study computerassisted personal interviewing (CAPI)

and audio computer-assisted

self-interviewing (Audio CASI)

questionnaires. It also describes the

Spanish translation process for the CAPI

and Audio CASI programs.

The questionnaire specification task

began soon after the contract was

awarded in 1992. NCHS staff had

drafted a paper-and-pencil questionnaire.

From this, an initial draft of

specifications, including skip patterns

and variants, was drafted and reviewed.

These specifications were given to

programmers, who wrote the program

code. The programs were tested, and, if

necessary, revised through more

specification and programming.

The pretest was then conducted,

pretest interviews were observed, the

results of the pretest data file were

examined, and the views of outside

experts were obtained to determine what

should be revised for the main study.

With this information, NSFG staff and

Table P. Unweighted sample sizes in the 1995 National Survey of Family Growth, by race/ethnicity and age

Race/ethnicity and age

Sample

count Eligible Located

Eligible

and located

Completed

interview

Total ....................... 14,000 13,795 13,243 13,038 10,847

15–17 years ................. 1,040 1,020 1,001 981 828

18–24 years ................. 2,622 2,586 2,452 2,416 2,106

25–29 years ................. 2,339 2,310 2,146 2,117 1,716

30–34 years ................. 2,815 2,783 2,656 2,624 2,165

35–39 years ................. 2,751 2,723 2,632 2,604 2,125

40–44 years ................. 2,433 2,373 2,356 2,296 1,907

Hispanic

Total ....................... 2,097 2,030 1,926 1,859 1,553

15–17 years . . . . . . . . . . . . . . . . . 139 133 134 128 126

18–24 years . . . . . . . . . . . . . . . . . 443 434 402 393 344

25–29 years . . . . . . . . . . . . . . . . . 416 399 365 348 284

30–34 years . . . . . . . . . . . . . . . . . 444 432 404 392 313

35–39 years . . . . . . . . . . . . . . . . . 380 369 358 347 278

40–44 years . . . . . . . . . . . . . . . . . 275 263 263 251 208

Non-Hispanic white

Total ....................... 8,166 8,084 7,885 7,803 6,483

15–17 years . . . . . . . . . . . . . . . . . 628 620 613 605 483

18–24 years ................. 1,486 1,469 1,417 1,400 1,215

25–29 years ................. 1,237 1,232 1,165 1,160 948

30–34 years ................. 1,583 1,571 1,531 1,519 1,259

35–39 years ................. 1,692 1,681 1,652 1,641 1,339

40–44 years ................. 1,540 1,511 1,507 1,478 1,239

Non-Hispanic black

Total ....................... 3,205 3,169 2,939 2,903 2,446

15–17 years . . . . . . . . . . . . . . . . . 221 217 207 203 178

18–24 years . . . . . . . . . . . . . . . . . 597 592 541 536 470

25–29 years . . . . . . . . . . . . . . . . . 606 601 545 540 437

30–34 years . . . . . . . . . . . . . . . . . 670 667 617 614 526

35–39 years . . . . . . . . . . . . . . . . . 584 581 533 530 437

40–44 years . . . . . . . . . . . . . . . . . 527 511 496 480 398

Non-Hispanic other

Total . . . . . . . . . . . . . . . . . . . . . . . 532 512 493 473 365

Page 18 [ Series 1, No. 36
the contractor modified the

specifications for the main study

questionnaire. These new specifications

were given to programmers, who revised

the program code. This semifinal

questionnaire was tested extensively. As

a result of this testing, additional

revisions were made to the program

code. Finally, interviewing began for the

main study. During fieldwork, a few

errors were discovered, and corrections

were sent out electronically to each

interviewer.

Pretest Questionnaire

Development

Questionnaire Assessment and

Specification

Shortly after the contract began, the

draft Cycle 5 questionnaire provided by

NCHS was assessed by the contractor to

determine if it could be programmed. As

with most paper-and-pencil

questionnaires for complex surveys,

further specification and clarification

were necessary before the questionnaire

could be given to CAPI programmers.

This task was complicated by the

significant expansion of the

questionnaire from Cycle 4 to Cycle 5.

In converting the survey to an

electronic instrument, a number of

issues had to be resolved

simultaneously. Many paper-and-pencil

questionnaires, especially those for

complex surveys, have ambiguous

concepts and routings that cause missing

or inconsistent data and are handled in

coding and editing after the interviewing

is over. CAPI programming, however,

demands that the routing and variants in

a question must be specified clearly and

in full detail before interviewing begins.

To move the interviewer accurately to

the next appropriate question or section,

detailed specifications identifying the

question(s) and answer(s) that determine

the correct path must be written and

then programmed. To ensure that the

interviewer read the appropriate wording

of a question, all possible wording

variations for a question were

programmed. The program chose the

appropriate wording based on answers

given to previous questions. As with

routing patterns, this process required

extensive specifications and

programming. Thus, when converting a

complex, ambitious survey questionnaire

from paper and pencil to CAPI, it is

common to have to ask many questions

to clarify concepts, routings, and

question variants, and to clarify how to

handle unusual situations.

In addition to these considerations,

findings from cognitive research were

used to improve the questions. When

this contract began in 1992, a small but

growing field of study used cognitive

psychology to analyze questionnaires

(20–22). However, a cognitive analysis

of the NSFG questionnaire had never

been done. Two technical reviews of the

questionnaire were conducted to

characterize the response tasks inherent

in the question-answering process and to

identify question characteristics that may

make it difficult for respondents to

provide accurate answers. For example,

a formal analysis of a draft of the

questions on family planning services

found that several technical terms were

used, along with complex reference sets,

shifts in the reference period, and long

recall periods (23). These are common

features of questionnaires on health care

and other technical topics, but they

make the respondents’ job more

difficult. Questions in the NSFG that

had these characteristics were identified

and resolved by NCHS and contractor

staff. The result was higher quality data.

In order to document questionnaire

concepts, routings, and revisions, a

detailed CAPI Reference Questionnaire

(CRQ) was developed to direct the

CAPI programming. The CRQ

development is described in the next

section.

Development of the CAPI

Reference Questionnaire

The CRQ was developed from the

draft Cycle 5 paper-and-pencil

questionnaire and from the ongoing

process of discussion and clarification

between NCHS and RTI staff. The CRQ

described the content of the CAPI

interview program and served as a

specifications document for the

programming staff. It was developed

through an interactive process in which

the paper-and-pencil questionnaire was

used to draft CRQ specifications for a

section, the section was reviewed,

comments were incorporated, and the

section was finalized. The CRQ

development task was a collaborative

effort in which close communications

were maintained via telephone,

electronic mail, written correspondence,

and face-to-face meetings.

The CRQ contained all of the

question and answer choices, transition

statements, routing instructions, and edit

and range checks implemented in the

CAPI and Audio-CASI programs. It also

contained all the wording variations for

each question, and specified routing

statements in a way that facilitated

programming. In addition, the CRQ

specified a substantial number of edit

checks, based on a review of the most

common edit problems in Cycle 4.

Variable names were assigned to each

question along with a unique question

number, reflecting the questionnaire

section in which the question appeared.

Where routing paths were unusually

complicated, the reviewers were also

given narrative descriptions detailing

how the CAPI program would handle a

question or series of questions. All of

these elements are illustrated in figure 4,

which is extracted from the CRQ. The

entire CRQ is about 385 single-spaced

pages in length, so it is not practical to

show all of it in this report. Instead, a

detailed outline of the questionnaire is

shown in appendix II. Readers who wish

to obtain a paper or electronic copy of

all or part of the questionnaire should

contact the Family Growth Survey staff

at NCHS, Room 820, 6525 Belcrest

Road, Hyattsville, MD 20782.

Draft versions of a CRQ section

were reviewed, updated, and saved as an

electronic text file (in WordPerfect)

before the section was programmed. The

CRQ was then used as a guide for

developing and testing the program.

Because the CRQ was the critical tool

for testing the CAPI program, it was

necessary to maintain an up-to-date

version of the CRQ throughout the

CAPI development and testing process.

Thus, as revisions were made to the

program, the CRQ was periodically

updated and redistributed, both

electronically and in hard copy.

Series 1, No. 36 [ Page 19
Laboratory Testing Before the

Pretest

Throughout 1993 and 1994,

considerable testing was done in both

the NCHS Laboratory for the Cognitive

Aspects of Survey Methodology and in

RTI’s Laboratory for Survey Methods

and Measurement. This section describes

only the testing done before the pretest.

As part of the pretest questionnaire

design process, five rounds of laboratory

testing were conducted at RTI to

examine specific sections of the

questionnaire. Think-aloud interviews

were conducted with about six

respondents in each of the five rounds to

obtain their opinions about the Life

History Calendar, the content of the

interview, the FoxPro Computerized

Method Calendar, and Audio-CASI. The

laboratory interviews before the pretest

had the following goals:

1. To examine the respondents’

understanding and preference for

different versions of computerized

and hard-copy Life History

Calendars.

2. To observe how the respondents

used the calendar and what types of

events they wrote on the calendar.

3. To ask how respondents answer

questions about their living

arrangements and sexual partners

and to observe how respondents

used the calendar when answering

these questions.

4. To use the CAPI program and see

how it works and how long it takes

to administer.

5. To observe the respondents’

reactions to the interview.

6. To get respondents’ reactions to the

Audio CASI interview.

These five rounds of interviews were

very helpful because they provided both

quantitative and qualitative data on how

the questionnaire worked. Revisions

were made and then tested again.

Pretest CAPI Programming

The pretest questionnaire was

programmed as sections of the CRQ

were completed. The 11 sections of the

questionnaire were programmed in 11

programming units, which roughly Figure 4. Example pages from the CAPI Reference Questionnaire

Page 20 [ Series 1, No. 36
corresponded to the sections of the

questionnaire shown in figure 3. Two

software packages, Blaise 2.5 and

FoxPro, were used. FoxPro was used to

develop an on-screen ‘‘Method

Calendar,’’ which contained a

month-by-month record of contraceptive

use from January 1989 until the Pretest

interview in 1993. All other CAPI

programs were written in Blaise 2.5, a

computer-assisted interviewing system

developed by The Netherlands’ Central

Bureau of Statistics. Originally, the

CASES computer-assisted interviewing

system was to be used, but in-depth

testing of the two systems indicated that

Blaise was a better choice for the

NSFG, primarily because it handled

rosters, or event histories, more

efficiently.

The versions of CASES and Blaise

available in 1992 were not powerful

enough for a survey as large as the

NSFG. Programming the entire

questionnaire as one or two units would

have been preferred, but the complexity

and length of the questionnaire and the

limitations of the software available at

that time made it necessary to break the

CAPI program into 11 units. Because of

the 11 separate programming units, data

had to be passed forward from unit to

unit, because question wordings, flow

checks, and edit checks depended on

responses from previous questions.

For the Blaise sections, an

authoring system was developed to

translate the WordPerfect questionnaire

specifications in the CRQ into first-stage

Blaise code. The code was then

manually edited by the programmers to

implement the routing patterns, edit

checks, arrays, and tables. Also, the

Audio CASI section was manually

edited to add audio capabilities.

The CAPI program was tested and

corrected on an ongoing basis

throughout the development process.

The NSFG staff worked closely with

RTI to ensure that the substantive

objectives of the survey were met, and

that the questions were clear and

understandable. As sections were

developed and tested, draft versions of

the CAPI program were provided to

NCHS. These drafts were reviewed and

revised as necessary until they were

ready for testing.

A systematic approach to testing

was used, requiring an up-to-date

version of the CRQ to be available at all

times as a reference document. This

systematic approach helped to maintain

control over the testing process and

ensured that the testing covered all parts

of the program. The CRQ was critical to

the testing process in that it documented

all questions and answer choices,

routing paths, and edit and range

checks. The testing included checking:

+ the routing for each response choice

for each question,

+ all wording variations and fills,

+ all major routing points or flow

checks, and

+ all edit and range checks.

A computer-generated checklist was

developed to help testers perform these

checks.

Two cautionary notes may be

gleaned from the NSFG’s experience.

First, while having a CRQ parallel to

the CAPI program is beneficial for

many reasons, it requires diligence to

update the CRQ as changes are made to

the CAPI program. Second, a CAPI

conversion effort of the magnitude of

the NSFG entails the likelihood that

necessary modifications and corrections

may be revealed at any time. These

corrections can make the schedule

somewhat unpredictable. For example, if

modifications have to be made during

the final phases of testing, interviewer

training and interviewing could be

delayed.

Revisions to the

Questionnaire for the Main

Study

NCHS staff analyzed information

from the Pretest data file, from

observations of Pretest interviews, from

debriefings of Pretest interviewers, from

the Workshop on the NSFG held in

January 1994 (figure 1), and from other

sources. This careful review led to a

large number of suggestions for

revisions to the CAPI program used in

the Pretest.

Principal Revisions

These revisions were intended to

improve the quality and usefulness of

the data, not to change the content of

the survey. Among the suggestions were:

1. Event histories—Suggestions for

modifications to the event histories

included asking separate education

questions for regular college,

vocational education, and General

Equivalency Degree (GED)

education; moving work history

questions to be near the education

and living arrangement questions;

and restructuring the sexual partner

questions. These changes required

significant reprogramming but

resulted in higher-quality, more

useful data; less sensitivity; and less

respondent burden.

2. Contraceptive use—The NSFG is a

survey about pregnancy. Since

contraceptive use is one of the most

important determinants of birth and

pregnancy rates, data on

contraception are some of the most

important data in the study. A

decision was made to collect the

method calendar information—the

month-by-month data on

contraceptive use and

pregnancy—entirely in Blaise, and

to drop the on-screen

(‘‘computerized’’) method calendar

that was used in the Pretest.

Although this change required

significant reprogramming, both

respondents and interviewers found

it much easier to use because the

paper method calendar was easier

for respondents to read. The Blaise

format also made it easier for the

interviewer to enter the data.

3. Family planning clinic database—A

national family planning clinic

database was added to the

questionnaire program. This required

additional programming and testing,

but it simplified the task for the

respondent. It was intended to

improve the quality of the data on

use of public family planning

clinics.

Series 1, No. 36 [ Page 21
The Revision Process

The questionnaire revision task for

the Main Study was a collaborative

effort between NCHS and the contractor.

Word processing software was used to

generate lists of revisions to each

questionnaire section. There was

continual consultation between NCHS

and the contractor to clarify the content

of questions and to determine the best

way to specify each question for

programming. Revised versions of a

CRQ section were provided for review

and comment before the section was

programmed.

As the revisions in the CRQ were

reviewed, effects on subsequent

questions, sections, or routing patterns

were examined carefully. As ambiguities

were addressed and clarified, the

annotated CRQ was provided to the

programmers. The CRQ for the Main

Study was about 385 pages long, and

revisions were necessary on

approximately 75 percent of the pages.

Figure 5 lists some of the more

significant questionnaire modifications

made between the Pretest and the Main

Study.

In addition to the section-specific

modifications, there were a substantial

number of wording and routing

revisions in all sections of the

questionnaire. These global revisions

included:

+ modifying the categories of medical

providers, and their on-screen

definitions (clinic, private doctor,

HMO, hospital emergency room,

etc.)

+ modifying the categories for

methods of payment questions, and

their on-screen definitions

(insurance, co-payment, Medicaid,

etc.)

+ modifying all tables and questions to

eliminate blank answer fields. This

change made data entry easier and

more accurate for interviewers

+ adding numerous on-screen notes

and definitions because they were

easier for interviewers to use than a

separate, hard-copy Questionnaire

Specifications Manual; and

+ increasing the number of

consistency checks within each

Figure 5. Significant revisions in the National Survey of Family Growth questionnaire

after the pretest

Page 22 [ Series 1, No. 36
section to enhance data quality—for

example, checking to see if start

dates were before ending dates, or if

recorded dates were before the date

of interview.

CAPI and Audio CASI

Development for the Main

Study

As individual sections of the CRQ

were revised and approved, they were

provided to the CAPI programmers for

coding. CAPI programmers specialized

in particular sections of the

questionnaire. The programmers used

the edited versions of the CRQ to

identify revisions required in their

assigned sections. They then made the

required changes in the CAPI program

and conducted the first round of testing.

Because of the number and

complexity of the revisions, it was

necessary to separate the programming

units of the questionnaire program and

test them individually. This process of

breaking apart the CAPI sections was

very time consuming for the

programmers, but it allowed other staff

to program and test sections

independently and concurrently, and that

saved valuable calendar time.

The interview driver program was

written in FoxPro. It linked the

programming units of the CAPI program

together to make the interview appear

seamless. This driver program checked

the validity of case ID numbers before

beginning the interviews, automatically

proceeded to the next section of the

interview as sections were completed,

rebooted to clear out memory before

and after the Audio-CASI section, and

generated a completed interview code

when an interview was completed. The

questionnaire was programmed in nine

programming units for the Main Study.

Summary Screens

The interview driver program did

not allow interviewers to back up across

programming units (previous

questionnaire sections) in either the

Pretest or the Main Study. Interviewers

were not allowed access to previous

sections for several reasons. First,

because of the length and complexity of

the questionnaire, it would have been

difficult and time consuming for an

interviewer to determine which question

required changing and to recall the

location of that question. Second, in

accessing completed sections, the

interviewer would have been able to

accidently change or delete answers.

Third, after changing an answer, the

interviewer would have had to check

subsequent sections to determine if the

new answer created routing problems or

inconsistencies in the data.

It became clear, however, that it

was necessary to give the interviewers

an opportunity to review and correct key

data items. This was based partly on

feedback received from the Pretest

interviewers regarding their inability to

back up and correct answers. The

concern was that incorrect responses to

key items would create situations in

which subsequent questions or sections

would be skipped in error. To prevent

such errors, ‘‘summary screens’’

(figure 6) were designed and

programmed at the end of Sections A,

B, C, D, and E (see figure 3) to give the

interviewers a chance to review the key

data items that had to be passed forward

to the subsequent sections. These

screens contained a list of the key data

items collected in the section; before

moving to the next section (or

programming unit), the interviewers

reviewed the listed items with the

respondent. If the interviewer and

respondent identified errors, they were

resolved before exiting the section,

allowing the CAPI program to pass

forward the corrected data. Figure 6

contains an example summary screen

from Section B of the CAPI program.

The Contraceptive Method

Calendar

A significant effort was required to

program and test the design changes for

the month-by-month contraceptive

method history for the 4 years before

the date of the interview. Using the

revised CRQ specifications, the FoxPro

calendar used in the Pretest was

removed from the CAPI program and

instead a Blaise method history module

was developed and tested. Screens

leading into the Blaise contraceptive

method calendar were added that

summarized the respondent’s

pregnancies and other related events and

prompted the interviewer to verify that

these were recorded on the respondent’s

Life History Calendar. The interviewer

then instructed the respondent to record

on the Life History Calendar all of the

methods she had used during the

specified time period, generally January

1991 to the date of interview. After all

methods were recorded on the paper

calendar, the interviewer entered them

into CAPI.

The FoxPro calendar, developed for

the Pretest, worked well—it had the

capacity to compute pregnancy start and

end dates, impute pregnancy intervals,

display recall cues and methods on the

calendar, and create the CAPI fills (the

text to be inserted in the method use

questions). It also performed a number

of detailed consistency checks to

promote more accurate reporting of

method use dates. But the Blaise module

was easier for respondents and

interviewers to use than the FoxPro

calendar, because:

1. The respondents and interviewers

preferred to use the paper Life

History Calendar rather than the

computer screen.

2. The paper Life History Calendar was

easier to read than the FoxPro

screen.

3. Using Blaise meant that the

interviewers could use just one kind

of software—Blaise—to collect

everything in the interview, instead

of having to learn a different

software package to administer the

method calendar.

In short, the FoxPro method calendar

was a technical success, but it was

replaced because it was not as easy to

use as the Blaise instrument and the

paper Life History Calendar. The new

Blaise version was very well received

by interviewers and respondents alike in

the Main Study.

The Family Planning Clinic

Database

Another significant CAPI

programming effort involved using a

Series 1, No. 36 [ Page 23
national database of family planning

clinics in Sections E and F. High-quality

data on how and where women obtain

their contraceptive methods is an

important objective of the NSFG. Data

were needed on the types of clinics

women use to obtain these methods in

order to evaluate the roles of private

doctors and public programs in

providing family planning services.

The Office of Population Affairs

(OPA) provided a current listing of

clinics in the United States that received

funding under the Federal Title X

program. This listing was used to

classify clinics according to Title X

status. For the 1995 NSFG, the Alan

Guttmacher Institute (AGI) provided a

comprehensive, computerized clinic

database that included the OPA listing of

Title X clinics. This database contained

approximately 7,000 family planning

clinics in the United States (24).

To ensure that the AGI database

incorporated all Title X clinics, the

latest OPA listing was merged with the

database. A special program was written

to detect misspellings of clinic names

and addresses, and city, street, and clinic

names that were too long. These were

corrected or shortened as required. After

this cleaning of the data file, the data

were sorted by city within State and

assigned sequential numbers to each

State, each city, and each clinic.

To select a clinic from the database,

interviewers were instructed to enter the

appropriate two-digit State code, the

two-digit city code in which the clinic

was reported, and the two-digit code

representing the reported clinic. If the

clinic was not listed in the database, the

interviewer asked for and recorded

verbatim the name and address of the

clinic. The database classified the clinic

in two ways: how they were

funded—that is, Title X funding versus

no Title X funding; and the affiliation of

the clinic—that is, hospital, Planned

Parenthood, health department, or other.

The computerized classification also

gave interviewers feedback on whether

the answer was complete enough to

classify.

Testing

The CAPI and Audio-CASI

programs were tested and debugged by

the CAPI programmers and project staff

on an ongoing basis throughout the

development process. As sections were

revised and tested, draft versions of the

Main Study CAPI program were

provided to NCHS for review and

comment. Meetings were held several

times during the development process to

review the program and to make

programming and questionnaire design

decisions.

The same systematic approach was

used in testing as was used during the

Pretest. A computer-generated checklist

of questions in each section was used to

ensure that each question had been

tested.

Tested sections of the CAPI

program were provided to NCHS on a

flow basis for review and comment.

Laboratory testing was performed by

NCHS on the Main Study questionnaire.

NCHS staff from the Family Growth

Survey Branch and the Office of

Research and Methodology interviewed

respondents who had been recruited

from the local community. Interviews

were meant to simulate portions of the

actual Main Study interviews, and

NCHS staff observed and kept track of

problematic questions and issues. These

became the basis for some of the

requested modifications and

improvements that were implemented.

As necessary, the CRQ and CAPI

program were revised and retested.

Once the individual sections had

been thoroughly tested, the systematic

testing was repeated on the whole CAPI

program. In addition to the testing done

for the individual sections (outlined

previously), the testing checked to

ensure that:

+ sections were linked correctly

+ needed data from previous sections

were available

+ procedures for ‘‘breaking off’’

(stopping) the interview worked

correctly

+ the program passed data from one

section to another as intended.

As a final check of the CAPI

program, mock interviews were

developed for the field interviewer

training program to test the questionnaire program. This served two

purposes: first, problems in the CAPI

program that would have arisen during

interviewer training were identified and

corrected before training; and second,

the accuracy of the training scripts could

be verified.

Figure 6. Example summary screen

Page 24 [ Series 1, No. 36
Spanish Translation

Once the English versions of the

CAPI and Audio CASI programs were

finalized, the questionnaire sections were

translated into Spanish. The translation

was done locally, allowing frequent

in-person interaction between the

translation service staff and the

contractor’s CAPI programmers and

questionnaire design staff.

In developing a protocol for the

translation process, several important

issues arose. First, it was important to

choose a dialect that would be

understood by all Hispanic respondents

regardless of their backgrounds. Second,

it was important that medical terms,

such as abortion, be translated

appropriately. Third, the placement of

the fill strings within the various

questions had to be resolved. Fills in

many of the English version questions

would have to be placed in a different

position in the Spanish version to make

the sentences grammatically correct.

A plan was developed for extracting

the English text from the CAPI

program, translating the text, and

merging the translated text back into the

CAPI program. The translator assigned

to the project was an experienced

computer programmer and brought to

the task an understanding of the

complex computer-related issues

associated with the extraction of English

text and replacement with Spanish text.

A bilingual survey specialist at RTI

tested drafts of the translated instrument

questionnaire several times.

After all sections were extracted,

translated, and merged, the program was

tested to determine that it worked. The

fills were revised as needed during this

process. Subsequently, the entire

interview was evaluated again and any

fills that still did not work properly in

translation were corrected.

For the Audio CASI portion of the

Spanish translation, a woman without a

notable Spanish dialect or accent was

used. The Audio CASI interview was

recorded in Spanish. This recording was

reviewed several times to identify any

problem areas and to rerecord them as

necessary.

Discussion

Although it was a time-consuming

and expensive process, using CAPI

offered the opportunity to build in

routing logic and edit checks that would

have been impossible for an interviewer

to implement properly on a

paper-and-pencil questionnaire. In

addition, using CAPI and the

programmed logic, routing, and edit

checks has resulted in a very clean

database that has greatly reduced the

amount of editing required. The efforts

expended in the redesign of the pretest

questionnaire for the Main Study

resulted in an improved CAPI

instrument that worked very well in the

field. Missing data is minimal. CAPI

and Audio CASI technology were

reliable and well accepted by both the

interviewers and the respondents.

Cycle 5 data suggest that the Audio

CASI methodology improved the

reporting of sensitive behaviors. The

Life History Calendar also worked well

as a recall aid for dates of pregnancy,

contraception, etc. Many respondents

liked seeing their major life events on

one page and asked to keep the paper

Life History Calendar.

Finalizing the CAPI questionnaire

and CRQ before starting programming

and testing would simplify CAPI

programming. The amount and

complexity of new questions made that

impossible in Cycle 5, but if it is

possible in the future, costs would be

reduced and the schedule would be

faster.

When the contract began in fall

1992, Blaise 2.5 was judged to be the

best CAPI software available for the

NSFG, in part because it handled

rostering so well. But Blaise 2.5 was not

designed to handle a questionnaire as

large and complex as the 1995 NSFG.

The questionnaire had to be

programmed into smaller questionnaire

units and linked with an external driver

program. Newer versions of CAPI

software and more powerful laptop

computers developed since then will

simplify the programming task.

The Cycle 5 CAPI program

included immediate consistency checks

of data and allowed the interviewer to

resolve the inconsistency while the

respondent was completing the

interview. When inconsistencies were

detected, scripted followup questions

were provided for the interviewer to use

in reconciling the data. These questions

for resolving inconsistencies need to be

written to describe specifically what the

interviewer needs to do to resolve the

inconsistency. The interviewers were

trained to enter comments whenever an

override occurred; however, they did not

always do so in the field. As a result, it

would be useful to add a question

immediately after any override that asks

the interviewer why she overrode the

edit check.

Interviewer Materials

This section describes the data

collection supplies and materials

developed for the NSFG Cycle 5

Main Study. The supplies and materials

included field manuals, materials for

locating and contacting respondents,

items used in obtaining participation,

computer hardware, Audio CASI

hardware, computer-related supplies, and

materials used during the interview. The

materials developed were revised from

those prepared for the Pretest.

Manuals

The manuals described in detail the

NSFG Main Study data collection

procedures and were used at training

and as a reference source during and

after fieldwork. The 261-page NSFG

Cycle 5 Field Interviewer (FI) Manual

was sent to each trainee about 1 week

before training, along with home-study

questions, which the trainees were asked

to complete and bring to training. The

331-page NSFG Cycle 5 Field

Supervisor (FS) Manual was distributed

to the supervisors several weeks before

supervisor and interviewer training. It

included all chapters from the

interviewer manual and an additional

chapter on supervisory procedures.

The Field Interviewer Manual

covered the background of the NSFG;

the role of the NHIS as the source of

the sample; the importance of

confidentiality and objectivity;

Series 1, No. 36 [ Page 25
procedures for contacting the sample

women; procedures for gaining

cooperation; how to administer the

questionnaire; how to use the computer

software, hardware, and the Audio CASI

equipment; quality control measures;

and how to report their time, effort, and

expenses.

The Field Supervisor Manual also

provided guidelines for assigning cases

to interviewers, monitoring field

activities, and conducting verification.

Materials Used for

Locating and Contacting

Respondents

A Case Assignment Folder (CAF)

was created for each sample woman,

with identifying information printed on

a label and affixed to the front of the

folder. The CAF contained case-specific

information, such as advance letters,

consent forms, brochures, and

information on advance tracing

activities. For Cycle 5, the field

interviewer mailed a personalized

advance letter to the sample woman a

few days before the interviewer would

try to contact her. Three versions of the

advance letter were developed: one to

adult sample women (18–44 years), one

to minor sample women (15–17 years),

and one to parents of minors in the

sample. Generic versions of each letter

were given to interviewers for sample

women who did not remember receiving

the personalized letter or requested

another copy. The generic advance

letters are shown in appendix III. The

letters were translated into Spanish for

sample women who were classified as

Hispanic in the NHIS.

Two ‘‘contact scripts’’ were

developed for interviewers to use when

making appointments to do the

interview or to obtain parental consent.

These ‘‘contact scripts’’ contained

questions that verified the identity of the

sample woman, questions for locating

the sample woman if she had moved,

and questions asking the sample woman

for a date and time to do the interview.

The two versions of the contact scripts

are shown in appendix IV.

Materials Used for

Obtaining Participation

Several items were used to help

obtain the participation of sample

women (or to obtain the consent of

parents). The advance letter, used to

make initial contact with the sample

woman (and her parents in the case of

minors), was also an effective tool for

obtaining participation. In addition,

various versions of refusal conversion

letters were developed. Each addressed a

different reason for refusal, including

being too busy, general uncooperation

by the sample woman, and general

uncooperation by the parent. A

‘‘gatekeeper’’ letter was also developed

to send to family members who were

unwilling to tell the interviewer the

whereabouts of a sample woman who

had moved. Refusal conversion letters

were sent by the supervisors after

consulting with the interviewer about

the circumstances of the refusal.

A picture identification badge was

provided to the interviewers. A Letter of

Authorization, shown in appendix V,

verified the interviewer’s position as an

interviewer on the NSFG. The NSFG

Q&A Brochure (see appendix VI) was

mailed to sample women (and parents)

with the advance letter.

The NSFG ‘‘Family Facts’’ sheet

and four newspaper articles reporting

data from the Cycle 4 NSFG were given

to sample women to demonstrate how

the NSFG data are used and reported.

The ‘‘Family Facts’’ sheet and the Q&A

Brochure were also included in the

‘‘gatekeeper’’ letter described previously

to emphasize the credibility of the study

to the family members of the sample

woman to allay any concerns about the

legitimacy of the study and encourage

them to tell the interviewer the sample

woman’s address or phone number.

Computer Hardware,

Audio CASI Hardware,

and Related Supplies

The hardware used in the NSFG

Main Study consisted of laptop

computers and audio equipment for the

field supervisors and field interviewers.

The supervisors were given printers.

Librex brand laptop computers were

obtained from the U.S. Bureau of the

Census. They had the following

specifications: 386 CPU; 4 MB of

RAM; 40 and 80 MB hard disk;

external floppy; external 19.2 modem;

and serial, parallel, and external VGA

output ports. The related computer

supplies included a power cord for the

computer, an external Librex diskette

drive, a 6-foot extension cord, a 3-

prong-to-2-prong power adaptor, an

Antex AudioPort sound box, a computer

cable for the sound box, a Sony headset,

a Multitech modem, a power cord for

the modem, a computer cable for the

modem, a telephone cord, a battery

charger, a power cord for the battery

charger, an extra battery, and a carrying

case large enough to hold all the

equipment.

Materials Used To

Administer the Interview

Question specifications for the

Cycle 5 questionnaire were provided on

the computer screen, in the Showcard

Booklet, and in the NSFG Cycle 5

Questionnaire Specifications Manual. A

Pill Chart, kept in a back pocket of the

Showcard Booklet, displayed pictures of

various brands of oral contraceptive

pills. This chart was shown to each

current user of oral contraceptive pills to

help her identify the brand and type she

was currently using.

An 11’ x 17’ paper Life History

Calendar (see appendix VII) was used to

help the respondent recall dates of

events asked in the interview. At the

beginning of the interview, the

interviewer described the purpose of the

calendar and went through an example

calendar that was displayed in the

Showcard Booklet. Then the respondent

and interviewer set up the calendar with

events from the respondent’s life.

During the interview, the respondent

was reminded to refer to the calendar to

help her recall dates and then to mark

these dates on the calendar.

Page 26 [ Series 1, No. 36
Discussion

The materials used worked well.

However, the external items on the

laptop computers (modem, audiobox,

and diskette drive) created some

frustration for the interviewers and

increased the training time and assembly

time for the interviewers. More modern

equipment with internal voice cards and

internal drives and modems should be

available for the next NSFG.

Interviewer Training

Training Program

T wo interviewer training sessions

were held to train 253 field

interviewers in January 1995, and

seven additional field interviewers were

trained in ‘‘attrition’’ training sessions in

April and May. The agenda for

interviewer training is shown in

appendix VIII. The training program had

four parts: preclassroom home study,

general computer training, NSFG

project-specific training, and Spanish

bilingual training. In addition, nightly

study halls were provided for

interviewers who were having difficulty

or had additional questions.

Preclassroom home study training is

a self-study of the Field Interviewer

manual with a written exercise.

Interviewers who had never used a

computer or were not regularly using a

computer were asked to attend a 4-hour

general computer training session to

learn how to use the Librex computer

and to go through a tutorial on the

NSFG questionnaire. The general

computer training was conducted by a

lead trainer and an assistant trainer and

was designed to give hands-on practice

with the computer.

NSFG project-specific classroom

training began with a plenary evening

session welcoming all trainees. Speakers

included the Chief of the Family

Growth Survey Branch of NCHS, the

RTI Project Director, and the RTI Field

Director. For the remaining 6 days of

the training, the trainees were divided

into small groups of 15 to 20

interviewers by supervisor region. Each

small group session had a lead trainer,

an assistant trainer, and a field

supervisor. The lead trainer gave most

of the lectures on data collection

procedures, led the various data

collection exercises, and gave

instructions on the computer hardware

and the software functions. Training on

the administering of the questionnaire

included three ‘‘round-robin’’ interviews,

during which trainees played the role of

the interviewer and the lead trainer

played the role of the woman being

interviewed.

The first 31⁄2 days of project-specific

training were devoted to administration

of the questionnaire. The content of the

questionnaire and its unique

characteristics were covered and use of

the hardware equipment was

demonstrated. Then a computerized

tutorial explaining how to use the

functions of the Blaise CAPI software

was reviewed by the lead trainer as the

trainees followed along on their

computers.

Three ‘‘round-robin’’ mock

interviews were conducted next. Each

round-robin interview was progressively

longer and more complex. Trainees took

turns asking questions, the lead trainer

gave the responses from a prepared

script, and the trainees entered the

responses into their computers.

Trainees were then paired by the

supervisors. Each pair of trainees

conducted two ‘‘paired mock’’

interviews using prepared scripts. They

also practiced data transmission.

On the fourth day of training, the

information about each sample woman

provided on the Case Assignment Folder

was discussed. Procedures for contacting

sample women and obtaining their

participation were described and

practiced. The fifth day of training

began with a discussion of field tracing

procedures for locating sample women

who moved; a 1-hour session on what to

do if a respondent becomes upset; and a

discussion on how interviewers should

document and report their time and

expenses. The session continued with

two more paired practice exercises

through the sixth day of training. During

the four paired practice exercises,

trainers evaluated trainees on their

ability to implement all key elements of

the interview process, including setting

up the computer and Audio-CASI

equipment, obtaining participation,

scheduling an appointment, completing

the Life History Calendar, and

administering the questionnaire. The

trainees were evaluated and ranked

because the contract required the

contractor to identify the lowest

25 percent of trainees, and to observe

their performance in the field. The last

day of training was devoted to

administrative responsibilities and use of

the computerized Field Monitoring

System. A discussion on procedures to

safeguard data quality, including field

supervisor observations and

verifications, was also provided. The

training ended with individual

conferences between each interviewer

and her supervisor to distribute

assignments. Interviewers were given

additional prepared interview scripts to

practice at home before going out into

the field.

Following the NSFG

project-specific training, interviewers

who were fluent in Spanish were asked

to attend the bilingual training session.

During this 4-hour session, the

interviewers reviewed and practiced

using the Spanish version of the CAPI

questionnaire. The Spanish CAPI

training was conducted by a field

supervisor who is fluent in both Spanish

and English.

The turnover rate among NSFG

interviewers was low. Two ‘‘attrition

training’’ sessions were held to replace

interviewers who had quit or had been

released from the study. Four

interviewers attended the first attrition

training session in April 1995, and three

interviewers attended the second session

in May 1995. These interviewers

received essentially the same training

program that the initially trained

interviewers had received. The training

schedule was modified to shorten the

discussion time in some areas because

the class size was smaller.

Discussion

Overall, the training program

worked very well in preparing the

interviewers to conduct the NSFG. The

special training session for interviewers

Series 1, No. 36 [ Page 27
inexperienced with computers, the

extensive use of hands-on practice, and

the availability of nightly study halls

gave the interviewers the confidence

they needed when they left training. In

retrospect, given the amount of effort

that had to be spent on finding

hard-to-locate respondents and on

refusal conversion techniques, some

trainees would have benefited from

some additional discussion of tracing

and refusal conversion.

Data Collection

Overview

This section describes the data

collection for the NSFG Cycle 5

Main Study. The field

organization for Cycle 5 consisted of

three major regions, each led by a

regional supervisor at the contractor’s

headquarters. Each region had 5

territories, for a total of 15. Each of the

15 territories was led by a field

supervisor. The field supervisors

prepared interviewer assignments and

were responsible for monitoring the

progress of each interviewer in their

region, performing field observations,

conducting telephone verifications of the

interviewers’ work, and conducting

refusal conversion efforts.

The field supervisors’

responsibilities were to analyze each

interviewer’s weekly production, to

review interviewer time and expense

reports for cost control information, to

develop tracing strategies, to talk to

each interviewer weekly to give

feedback on all of these issues, and to

provide support. To accomplish this, the

supervisors held a regularly scheduled

phone conference with each interviewer

every week. In addition, the supervisors

were available to their interviewers as

needed. Following their interviewer

calls, the five field supervisors in each

region made weekly progress reports to

their assigned regional supervisor.

Throughout the fieldwork, the field

staff were supported by a computerized

survey control system. This system was

developed to track each case from the

time it was selected for the sample, to

when it was assigned to an interviewer,

to when the interview was completed,

and when the data were transmitted to

the RTI home office. The system

captured pending and final result codes

and monitored the transfer of cases

between field staff. The system consisted

of two primary components: the

in-house Control System and the Field

Monitoring System. The Control System

resided on RTI’s mainframe computer; a

copy of the Field Monitoring System

resided on each interviewer’s laptop

computer. The system generated both

daily and weekly reports to show the

status of each case for the day before.

Old paper-and-pencil field monitoring

systems provided data that were 7–10

days old. In the 1995 NSFG, the data

were only 1 day old. Reports were run

by interviewer, by field supervisor area,

by regional supervisor territory, and for

the total sample. The supervisors

received their reports electronically.

Electronic reports were also sent daily

to the Family Growth Survey Branch for

the first few weeks, and then twice a

week, for its use in monitoring the field

work.

A total of 260 interviewers worked

on the Cycle 5 Main Study. Because of

the survey’s subject matter, all were

female. Data collection began

immediately after the initial training

session on January 13, 1995, and was

originally scheduled to end on June 15,

1995, but was extended until July 31.

Later, data collection was extended

again, to allow for additional tracing by

the U.S. Bureau of the Census.

Completed interviews were obtained

from 10,847 sample women. Completed

interviews were telecommunicated to the

contractor’s host computer each evening.

In the following sections, a number

of aspects of NSFG fieldwork are

discussed: the field organization, staff

recruitment, interviewer assignments,

locating sample women, interviewing

sample women, refusal conversion

procedures, data collection extension,

data collection reports, and data

collection results.

Field Organization

The sample for the 1995 NSFG was

obtained from the 1993 NHIS. This

NHIS-linked sample design drew

women from 198 PSU’s in the United

States, including Alaska and Hawaii.

The 198-PSU design in Cycle 5 means

that the sample was more dispersed than

in previous cycles of the NSFG: Cycle 4

used 156 PSU’s, and Cycles 2 and 3

used only 79 PSU’s. The smaller

number of PSU’s and segments in

previous Cycles tended to reduce the

costs of those earlier surveys but also

increased their sampling errors (table C).

Thus, fieldwork costs for previous

Cycles were lower, and variances larger,

than in the 1995 NSFG.

Assignments were made in an effort

to provide a reasonably equitable

distribution of sample cases and thus an

equitable number of interviewers

assigned to each supervisor. Supervisory

regions included contiguous areas but

were not necessarily drawn to coincide

with State boundaries because of the

need to balance workloads among

supervisors. More experienced

Table Q. The number of sample women and estimated number of field interviewers by supervisory regions as assessed in 1994

Regions

Number of

field

supervisors

Total

sample

women

Expected

number of

completed

interviews

Projected

number of

field

interviewers

Calculated

number of

field

interviewers

North Eastern .............. 5 4,906 3,690 92 90.84

South Eastern .............. 5 4,512 3,400 84 83.72

Western .................. 5 4,582 3,445 86 84.86

Total . . . . . . . . . . . . . . . . . . . . 15 14,000 10,535 262 259.42

Page 28 [ Series 1, No. 36
supervisors were given larger territories.

Regions were also set up so that no

region included more than two of the

following cities: New York,

Philadelphia, Detroit, Washington, D.C.,

Chicago, Miami, Dallas, Houston, and

Los Angeles. These are the cities in

which response rates tend to be the

lowest, costs highest, and interviewer

turnover greatest. Table Q shows the

number of sample women and estimated

number of field interviewers needed, by

region, as assessed in 1994, just before

fieldwork began.

Interviewer Assignments

Field supervisors were responsible

for making case assignments to the

interviewers in their assigned PSU’s;

13,125 cases from 198 PSU’s were

assigned. A reserve sample of 875 cases

was fielded toward the middle of the

data collection period to ensure that at

least 10,500 completed interviews were

obtained. The following were

considerations for making interviewer

assignments:

+ the geographic location of the cases

in each site

+ the location of the interviewer’s

residence in relation to the cases

+ the number of hours per week that

the interviewer committed to the

project

+ the ability and efficiency of the

interviewer based on her previous

experience, observations, and ratings

during training

+ the race/ethnicity and bilingual

capability of the interviewer.

Field interviewers and respondents

were matched based on race/ethnicity

when possible, but because of the

dispersion of the sample, and because

the interviewer’s skills and experience

were more important than their race, it

was impossible to match everyone. The

results of matching interviewer and

respondent were as follows: 38 percent

of Hispanic respondents were

interviewed by Hispanic interviewers;

29 percent of black respondents were

interviewed by black interviewers; and

92 percent of white and other

respondents by white and other

interviewers.

Interviewing Sample

Women

The initial contact with a sample

woman was made with an advance letter

(see appendix III). The letter was

personalized for each sample woman

and was included in the Case

Assignment Folder when assignments

were given to the interviewers. The

interviewers mailed the letter to the

sample woman a few days before

beginning work on that case. Given the

lengthy data collection period, this

mailout procedure was preferred over a

‘‘mass mailing’’ because it meant that

the sample woman would receive the

letter as close as possible to the time

she was contacted by the interviewer.

When the field interviewers

contacted a sample woman (or her

parent), they introduced themselves and

explained the purpose of the study,

referring to the advance letter that the

sample woman should have already

received. The interviewer then attempted

to obtain parental permission when

needed and arranged for a private

setting for the interview. Next, the

interviewer set up the computer

equipment and conducted the interview

using CAPI and Audio-CASI. When the

interview was completed, the

interviewer gave the respondent the $20

incentive and a letter that thanked the

respondent for participating in the

interview.

In 218 cases (2 percent of the

10,847 completed interviews), the

interview was conducted by telephone

rather than in person. This was allowed

only when the respondent insisted that

she would not allow the interviewer to

come into her home and would not

agree to meet the interviewer at a

neutral location to complete the

interview, or if the case was in a remote

area and the cost of sending an

interviewer to the area to complete one

case would have been prohibitively

expensive. Before telephone interviews

were conducted, prior approval had to

be received from one of the three

regional supervisors. The respondent

was mailed the Life History Calendar,

and the interviewer helped her fill it out.

Data Collection Results

In appendix IX, a summary of the

results from the data collection status

reports is presented. Results are

presented for totals and by region,

race/ethnicity, age, and income.

Characteristics (race, income, and date

of birth) were obtained in the 1993

NHIS, about 2 years before the 1995

NSFG. NSFG interviews were

completed with 10,847 women out of

13,795 eligible women, for an overall

(adjusted) response rate of 79 percent.

As shown in appendix IX, table 1, the

response rate for Region 1 (the

northeastern States) was 80 percent; for

Region 2 (the southeastern States) it was

75 percent; and for Region 3 (the

western half of the United States) it was

81 percent. As shown in appendix IX,

table 1, the most common types of

nonresponse were inability to locate the

woman (5 percent) and refusals

(11 percent).

As shown in appendix IX, table 2

and table R, there was little difference in

the adjusted response rate by race and

ethnicity (79 percent for Hispanic and

other women and 78 percent for black

women). The refusal rate for white and

other women was 13 percent compared

with 8 percent for black and 9 percent

for Hispanic women. On the other hand,

the percent unlocatable (untraceable)

was 8 percent for black and Hispanic

women and only 4 percent for white

women. Thus, the similar response rates

for the three groups occurred because of

the higher refusal rates for white

(‘‘other’’) women and the higher percent

unlocatable for black and Hispanic

women.

Appendix IX, table 3 shows that the

adjusted response rate was higher for

women under 18 years of age

(82 percent) than for women 18 years of

age and older (78 percent). Women 18

years of age and older had slightly

higher percents unavailable and

unlocatable than women under 18 years

of age. Table R summarizes data from

appendix IX, tables 2, 4, 7, and 8.

Appendix IX, table 4 shows that

9 percent of low-income sample women

were unlocatable, compared with

3 percent of high-income women. On

the other hand, high-income women had

Series 1, No. 36 [ Page 29
higher refusal rates (14 percent) than

low-income women (8 percent). The

adjusted response rate was 77 percent

for low-income and 78 percent for

high-income women. The lower refusal

rates for low-income women suggest

that the incentive offset the bias that

would have been caused by the inability

to locate low-income women.

Table R shows that the adjusted

response rates were about equal for the

two income groups (77 and 78 percent),

for both black (75 and 77 percent) and

white (‘‘other’’) women (78 and

79 percent). However, the components

of nonresponse were quite different for

the two income groups. For low-income

black and Hispanic women, the percents

unlocatable were much higher than the

percents refusing. For example,

14 percent of low-income Hispanic

women could not be located, while only

6 percent refused.

In contrast, for high-income

Hispanic women, just 4 percent could

not be located, and 11 percent refused.

For high-income women, only 2 percent

could not be located and 15 percent

refused. With the linked sample,

however, it was possible to identify and

adjust for these differences (16).

Interview Length, Tracing,

and Response Rates

The Cycle 5 data collection strategy

and results were affected by the linked

sample design and by the length of the

questionnaire (see table S).

The Linked Design

As a result of the advance tracing

and field tracing efforts described in the

‘‘Tracing’’ section, 95 percent of the

selected sample women were located.

This result, however, left 5 percent

unlocated and without an opportunity to

participate in the survey. If these

5 percent had cooperated at a rate

similar to the 95 percent located, the

response rate for the survey would have

been around 83 percent.

Interview Length

It also appears that the length of the

interview made it difficult to obtain high

response rates. In general, most women

found the subject matter important and

interesting. However, women in the

NSFG age range typically are busy with

school, work, and families. The Q & A

Brochure disclosed that the interview

would average about 90 minutes. Given

this information, the most prevalent

reason given for not participating in the

survey was ‘‘lack of time.’’ The length

of the interview may have also affected

the interviewers’ performance. The

interview length affected the times of

day the interview could be done (for

example, after 8 p.m. may not allow

enough time in some cases). The

interview length may have also affected

the interviewers’ assertiveness. They

could not encourage participation by

saying that the interview would be short,

because in many cases it could continue

for 2 hours or more.

The experience of Cycle 5 suggests

that the following factors would make

fieldwork easier and reduce costs in

future cycles:

1. More complete and accurate locator

data from the NHIS (name, date of

birth, contact person information,

and Social Security number)

2. A shorter interval between the NHIS

and the NSFG, which would allow

less time for sample women to move

3. Some form of contact with the

sample to summarize the results of

the NHIS, to tell them that their

participation is important, and to

Table R. Percent unlocatable, percent refused, and response rate, by race/ethnicity and National Health Interview Survey income: 1995

National Survey of Family Growth

Income Hispanic Black Other Total

Total Number

Total cases assigned .................... 1,843 2,818 7,930 12,591

Percent

Unlocatable .......................... 8 8 4 5

Final refusal . . . . . . . . . . . . . . . . . . . . . . . . . 9 8 13 11

Adjusted response rate . . . . . . . . . . . . . . . . . . 79 78 79 79

Income under $20,000 in 1993 Number

Total cases assigned . . . . . . . . . . . . . . . . . . . . 930 1,567 2,066 4,563

Percent

Unlocatable . . . . . . . . . . . . . . . . . . . . . . . . . . 14 12 7 9

Final refusal ......................... 6 7 8 8

Adjusted response rate . . . . . . . . . . . . . . . . . . 75 75 78 77

Income $20,000 or higher in 1993 Number

Total cases assigned . . . . . . . . . . . . . . . . . . . . 913 1,251 5,864 8,028

Percent

Unlocatable .......................... 4 5 2 3

Final refusal . . . . . . . . . . . . . . . . . . . . . . . . . 11 11 15 14

Adjusted response rate . . . . . . . . . . . . . . . . . . 81 77 79 78

NOTE: The sample sizes in this table enable 95 percent confidence intervals of less than ± 3.2 percent for Hispanics, ± 2.9 percent for non-Hispanic blacks, and ± 2.1 percent for other race/ethnicity.

Page 30 [ Series 1, No. 36
request an update of their address

and telephone number

4. A shorter interview

5. A larger incentive.

In July 1995, at the scheduled end

of the Cycle 5 data collection period, a

decision was made to extend the data

collection period through October to

allow the U.S. Bureau of the Census to

trace the remaining hard-to-locate cases

and to allow the RTI field staff to work

the nonresponse cases and any newly

located cases more completely. This

effort increased the overall response rate

to 79 percent; but the average field cost

per interview during the extension was

significantly higher than the field costs

during the initial field period.

It appears that the $20 incentive

payment increased response rates. In the

Pretest, incentives raised the response

rate by approximately 7 percentage

points and reduced interviewer effort

more than enough to pay for the

incentive. It is unclear, however, what

impact a larger incentive ($30 or $40)

might have. This issue deserves further

study; both larger incentives and shorter

questionnaire length might be tested to

observe their effects on field costs,

response rates, and the reporting of

sensitive items.

Quality Control

Introduction

Quality control was important in

all stages of the NSFG data

collection process. This section

discusses the quality control procedures

that were put in place during training

and data collection.

Practice, Monitoring, and

Evaluation at Training

An essential part of interviewer

training involved hands-on practice

(practice conducting the interview, using

the computer, etc.). To make sure that

interviewers were properly prepared for

their assignments, RTI trainers and

NCHS staff monitored interviewers

during the training session. After the

training session each day, the lead

trainers met with other project staff to

discuss the progress of training, identify

interviewers who were having difficulty,

and decide how to help them.

During the last half of training,

each interviewer was paired with

another interviewer for paired mock

interview practice. Paired mock scripts

had been specially designed to make

sure that the interviewer was equipped

to handle situations that would

commonly arise in the field.

During the paired mocks, the lead

trainer and field supervisor assessed and

evaluated how well the trainees

performed as they were:

+ setting up the computer and Audio

CASI equipment

+ explaining, setting up, and using the

Life History Calendar

+ obtaining and keying the work

history

+ obtaining and keying the living

situation history

+ using computer functions to resolve

edit problems

+ resolving inconsistent dates

+ probing effectively to help the

respondent recall dates

+ using computer functions (for

example, keying ‘‘don’t know’’ and

‘‘refused,’’ entering comments, etc.)

+ using the clinic database

+ obtaining and keying the birth

control methods history

+ using specifications on the computer

screen, in the Showcard Booklet,

and in the Specifications Manual

+ explaining the purpose of Audio

CASI to the respondent

+ explaining the keyboard and the

Audio CASI function keys to the

respondent

+ performing general interviewing

techniques, such as reading the

questions, pacing the interview, and

probing appropriately.

Observers completed a form that

included these evaluation points. The

interviewers who had the most difficulty

Table S. Mean (average) and estimated mean time (minutes) time required to complete the interview, by section of the questionnaire: 1995

National Survey of Family Growth

Section N1

Mean time

(minutes)2

Estimated mean2

(minutes)

A ........................... 10,520 21.5 22.2

B ........................... 10,533 9.2 9.9

C ........................... 10,532 10.7 11.4

D ........................... 10,534 2.5 3.2

E ........................... 10,536 15.1 15.8

F ........................... 10,530 4.3 4.3

G ........................... 10,537 1.3 1.3

H ........................... 10,535 4.0 4.7

I............................ 10,477 17.3 18.0

J (Audio CASI) ................... 10,517 7.9 12.5

Total3 ........................ 10,401 103.3 103.3

1N is the number of cases used to compute the mean, that is, with complete data on interview length.

2Total includes times between sections while the interviewer driver program wrote out the first section data, got out of the first section, started the new section, and the interviewer asked the first

question and recorded the response to the first question. This time is estimated at 4.9 minutes (0.7 minutes per section—or 42 seconds). Time getting into and out of Audio CASI, or Section J, is

estimated at 4.6 additional minutes. These estimates are shown in the ‘‘Estimated mean’’ column.

3Total does not include about 2 minutes to complete Section K and pay the incentive.

Series 1, No. 36 [ Page 31
were further evaluated by the trainers

and field supervisor. Some interviewers

were instructed to practice more at

home before they received any cases to

interview.

A nightly 2-hour study hall staffed

by at least one trainer was used as one

remedial measure for interviewers who

were having difficulty with the material.

Any interviewer who had questions, or

wanted assistance or more practice was

free to drop in during that time. If an

interviewer was far behind her

colleagues, study hall attendance was

mandatory. Many study hall attendees

grasped the basic concepts of the

interview but gained confidence from

the extra practice.

Interview Observations

Field Supervisor Observations

As mentioned previously,

interviewers were observed by the

trainers during paired mock interviews

at interviewer training. The field

supervisor observed actual interviews in

the field for the 25 percent of

interviewers from her area who had the

worst scores at training. The sample

woman was asked if the field supervisor

could observe her interview. During the

interview, the field supervisor completed

an Observation Evaluation Form that

was very similar to one used at

interviewer training. Field supervisors

also documented specific questions that

proved difficult and listed detailed

information on what the problem was.

After the observation, the field

supervisor discussed the positive aspects

of the interview as well as areas that

needed improvement. Also at that time,

the field supervisor edited completed

Case Assignment Folders and gave

interviewers the chance to ask questions

about their assignment or performance.

NCHS Staff Observations

Actual interviews were observed by

NCHS staff in several locations. Due to

the nature of the study, only female staff

conducted observations. The purpose of

these observations was to determine

how well the questionnaire worked and

to identify specific questions that caused

problems for respondents or

interviewers. Observation reports

indicated that most interviewers

performed their duties well.

Verification

In order to provide feedback to the

interviewers on the quality and accuracy

of their interviews, an intense

verification process was used. All NSFG

verifications were completed by the field

supervisors for their own regions so

they could promptly reach the

interviewer to seek clarification if a

problem was identified.

The process of verifying fieldwork

was a critical component of the overall

quality control system. Both ineligible

and completed interview cases were

selected for verification. Whenever

possible, verifications were completed

by telephone. In a few cases where the

respondent did not have a telephone and

lived close to the field supervisor,

in-person verifications were conducted.

Weekly verification reports were

generated and provided to NCHS. For

the most part, interviewers’ work

verified with no problem. However, field

supervisors discovered four interviewers

who falsified work. When falsification

was discovered, the interviewer’s

employment was terminated. Whenever

possible, the falsified cases were

assigned to another interviewer for

completion.

Discussion

Training

Quality control measures put in

place for training went well. By having

informal discussions about interviewers

who were having difficulty, remedial

steps were taken quickly to bring them

up to an acceptable performance level.

In addition, by offering study hall

nightly, one-on-one help was provided

and the comfort level of interviewers

who may have been struggling was

increased. Paired mock observation was

useful and allowed field supervisors to

observe each interviewer’s strengths and

weaknesses.

Interviewer Observations

It was useful for field supervisors to

observe the weakest trainees in the field.

However, it might be more useful to

rank all of the interviewers across the

country and observe the worst

25 percent of those, rather than

25 percent for each region. This way the

interviewers who have the most

problems (regardless of where they

work) would be observed.

The contract required that the

weakest 25 percent of field interviewers

be observed in person. While it is

difficult to predict what proportion of

the interviewers hired for a study as

complex as the NSFG would require

remedial work and field observations,

our experience suggests that 25 percent

may be higher than necessary. Given the

cost of the in-person visits, it might be

sufficient to observe the weakest 10 to

15 percent of interviewers.

Timeliness of Verifications

Given that four interviewers were

caught falsifying data, it is clear that the

verification procedure was worthwhile.

However, one problem encountered was

the timeliness of the verification. Field

supervisors often felt overloaded and

verification was often the task given the

lowest priority. One option for

addressing this issue is to limit the ratio

of supervisors to interviewers at 1:16.

Two-thirds of the supervisors had more

than 16 interviewers assigned to their

area. Or someone other than the field

supervisor could conduct

verification—for example, a quality

control assistant to the field supervisor,

a regional supervisor, or other person

knowledgeable about the study could

conduct the verification.

Data Processing

Overview

The questionnaire was not the only

part of the 1995 NSFG that was

computerized. Computing

support spanned the full range of

activities, from sampling through the

Page 32 [ Series 1, No. 36
delivery of the final data files. In-house

and field monitoring systems allowed

the contractor and NCHS to monitor the

progress of all project operations and to

complete project tasks as quickly and

efficiently as possible. In addition to

programming the CAPI questionnaire

(as described in ‘‘Questionnaire

Development,’’) the contractor’s

computing staff:

+ updated addresses, phone numbers,

and contact information for sample

women who moved or changed their

names

+ printed personalized advance letters,

personalized tracing forms,

personalized case assignment folder

labels, thank-you letters, and other

interviewer materials

+ tracked the daily progress of the

fieldwork for each sample member

+ produced fieldwork status reports for

the nation, for the 15 regions, and

for each of the interviewers

+ enabled field supervisors to transfer

cases electronically from one

interviewer to another

+ devised an electronic mail system to

communicate with the field

interviewers and field supervisors

+ enabled field interviewers to send

completed interview data

electronically to the contractor’s

central office

+ made corrections to the CAPI

interview program after interviewing

began, and sent the updated software

to the interviewers electronically

+ edited completed interview data

after they were received at the

central office

+ coded 19,800 occupations and

industries; 32,000 other (specify)

responses; and address data for each

respondent for 1990, 1993, and

1995, and

+ prepared and delivered data files

with codebooks and documentation

from the NSFG interviews, the

survey control system, the NHIS,

and the interviewer characteristics

file.

The computer support tasks on the

NSFG are described in greater detail in

the rest of this section.

In-house Survey Control

System

A computerized Survey Control

System was developed to track each

case from sample selection through

advance tracing, producing advance

letters, assignment to an interviewer,

verification, and final receipt of the data

and the Case Assignment Folder at

RTI’s headquarters. Reports were

produced with this tracking system that

enabled costs and production to be

monitored. It also allowed the

supervisors to monitor overall

production, production for each field

interviewer, and potential refusal and

unlocatable cases. The system assigned

pending and final disposition codes and

monitored the transfer of cases between

field staff.

The control system resided on a

VAX computer system and was written

in FICS (the contractor’s Fully

Integrated Control System software) and

FORTRAN. FICS programs were used

to manage the databases and generate

the reports, while FORTRAN programs

were used primarily to process the case

assignment and transfer orders. The

majority of the information for the

in-house control system was entered by

the field interviewers. The system was

set up to run automatically each night

during data collection and to distribute

reports to NCHS via computerized fax,

to contractor staff via e-mail, and to the

field staff through the data transmission

process.

Two primary databases, NSFGAT

(NSFG Advance Tracing) and FGCS

(Family Growth Control System) were

established; both were managed by the

FICS Control System software. The

NHIS preload data included the names,

addresses, phone numbers, dates of

birth, marital status, and Social Security

numbers for the selected sample. It also

included names and addresses for the

NHIS reference person and sometimes

an additional contact person. All tracing

forms, advance letters, Case Assignment

Folder labels, and thank-you letters were

printed using this database. When the

NHIS preload data were received, they

were loaded into NSFGAT, the database

used to track all tracing operations and

maintain the most up-to-date addresses

and phone numbers in addition to all

known address and contact information.

The FGCS database was used when

interviewing began. The FGCS

maintained a history of the status of

each case and tracked all case

assignments and Case Assignment

Folders. The FGCS database was the

source of information for all daily status

and verification reports.

Field Monitoring System

The Field Monitoring System

(FMS) was used by the field

interviewers and their supervisors to

track cases, enter disposition codes,

transmit data, and assign and transfer

cases to field interviewers. (Only field

supervisors could transfer cases from

one interviewer to another.)

The FMS enabled the NSFG field

staff to search and view cases by

identification number or name. The field

interviewers used this system to enter

‘‘disposition codes’’ that indicated what

they had done on each case and to

change the codes when necessary.

Cases were often transferred to

another interviewer or a different

supervisor if the respondent had moved

out of the original supervisor’s area.

Supervisors also had to transfer cases

from the interviewers back to

themselves to assign final disposition

codes.

Field Reports System

The Field Reports System (FRS)

gave the field supervisors easy access to

daily field status and other reports. The

FRS picked up any new reports as part

of the daily data transmission and

displayed a list for the supervisors’

selection and viewing. Information in

the daily reports sent to NSFG field

supervisors included:

+ totals by the three regional

supervisors

+ totals for the field supervisor

+ data for each of the field

supervisor’s interviewers

+ a list of Case Assignment Folders

that needed to be returned

Series 1, No. 36 [ Page 33
Data Transmissions

NSFG data were transmitted

automatically at prescheduled times. The

system waited until the assigned time to

dial in. Dial-ins occurred at staggered

times late at night. The system also

allowed immediate dial-in as an option

when necessary. The data transmission

process prohibited the field interviewer

from using the telephone only during

the actual data transmission call. The

data transmission component for NSFG

handled approximately 150 calls per

night and about 25 immediate calls

(mostly from supervisors) per day.

The data transmission software

transferred mail files and data files, as

applicable, every time a connection was

made. This software was also used to

send case assignments to interviewers

and transfer cases from one interviewer

to another.

All data stored on the laptops were

secured by using password-protected

computers. The interview data on the

laptops were also protected by

prohibiting anyone from accessing a

case after it was completed. After the

interview data were transmitted, they

were stored on the contractor’s

password-protected VAX computer.

The data transmission software was

also used to make changes and

corrections in the various programs on

the interviewers’ laptops. During the

data collection period, revised

questionnaire Sections A and E, three

versions of the field monitoring system

software, an upgraded version of the

PT&E data entry program, and modified

case transfer software were transmitted

to the interviewers and supervisors.

Finally, the software was designed

for timely detection of any possible field

problems, such as transmission

problems, completed interview and final

event code mismatches, incomplete case

transfers, missing questionnaire sections,

or undelivered mail messages.

Data Editing Procedures

The Family Growth interview data

were edited using a number of programs

written specifically for the NSFG. The

editing programs were based initially on

the CAPI Reference Questionnaire

(CRQ) specifications. The edits were

expanded as a review of the data and

interviewer comments pointed out

inconsistencies. A team of contractor

staff was involved in writing edit

programs, resolving problems, and

conferring with NCHS staff on

particularly difficult problems.

(Examples of interviewer comments are

shown in figure 7.)

The first editing step was to write

SAS programs to identify

inconsistencies in the completed

interviews. These programs reproduced

the Edit checks specified in the CRQ. A

separate program was written for each

questionnaire section. The programs

were used to ‘‘machine edit’’ the data.

As completed interviews were

received, the edit programs were run

and the results reported to the data

editors. The data editors worked closely

with NSFG staff to develop and

document rules for resolving the

inconsistent answers.

At regular intervals during data

collection, the SAS edit programs were

run on all newly completed interviews.

At the same time, interviewer comments

for those cases were extracted. Every

interview that had either an edit failure

or an interviewer comment was then

loaded into the Blaise CAPI software on

a laptop computer to resolve the

inconsistency. Loading the cases into

Blaise was necessary to maintain the

integrity of the flow checks. When a

response to a question was changed, it

often meant that additional questions

should have been asked or previously

asked questions should be skipped.

Using the Blaise interview software, the

additional questions were asked of the

editor, a survey specialist who was

familiar with the questionnaire. If the

editor could determine the correct

response from an interviewer comment

or from other data, he or she entered the

data. If the correct response could not

be determined, a missing data response

was entered. Whenever response

changes caused questions to become

inapplicable, Blaise automatically made

those fields blank. All changes were

reviewed by the editors to ensure

accuracy. During the course of the

Page 34 [ Series 1, No. 36

Figure 7. Examples of interviewer comments
study, 1,582 edit failures and 6,919

interviewer comments were identified.

Figure 7 shows examples of

interviewer comments. Only a small

proportion of the interviewer comments

resulted in changes to the data.

In addition to the main SAS edit

programs, several other programs were

written to identify and/or correct

unanticipated inconsistencies. If the

problem was narrow in scope and could

be fixed using a program rather than

manual editing, a program was used.

Otherwise, the cases were edited

manually.

Some examples of the types of edits

that were performed are given below.

Variable names in this and subsequent

sections are presented in UPPERCASE,

UNDERLINED print.

+ Editing VOCEDNOW (Are you

currently in a vocational education

program?): For the first run of the

Section A SAS edits, several cases

failed the edit check because the

respondent reported that she was

currently in a vocational education

program (AB-27 VOCEDNOW =

yes) but the end date recorded for

the last period of attendance

(AB-31VOCSTOP) was not the code

used for ‘‘still in the program.’’ It

was found that the edit check in the

CAPI program was not working

properly. To fix the problem, the

Blaise program was corrected and

the updated program was

downloaded electronically to the

interviewers’ laptops. Also, a

program was written to correct the

data that had already been collected

and transmitted to the contractor.

+ Changes to pregnancy sort order:

Sometimes, as a result of

interviewer comments, pregnancy

end dates were revised by the

editors, which changed the order of

the pregnancies. As a result, answers

to the ‘‘wantedness’’ questions for

some of these cases were no longer

associated with the correct

pregnancies. Programs were written

to check for revised pregnancy end

dates and programming staff

determined how the revisions

affected the data. One program

identified the affected cases; after

manual review to determine the

correct order, a second program

copied the data to the appropriate

‘‘wantedness’’ positions. There was

no manual editing to fix this

problem except to verify that the

program ‘‘fix’’ was working

correctly.

+ Clinic database lookups: During the

interview, respondents reported

using 1,775 ‘‘clinics’’ for family

planning or medical services that the

interviewers were not able to locate

in the clinic database. After data

collection, an updated version of the

Alan Guttmacher Institute (AGI)

family planning clinic database was

compared with the one used in the

field. New clinic codes were created

for the additional family planning

clinics. Using the merged clinic

database and a list of names and

addresses for the 1,775 uncodeable

clinics, the contractor successfully

located 597 of these clinics. This

new information was then

programmatically edited back into

the interview data files along with

Title X status and ‘‘type of agency’’

information. This editing process

took considerable effort, but it was

justified by the importance of the

data on Title X clinics.

Data Coding Procedures

Most coding was done

automatically by the CAPI system.

Some types of coding, however,

required staff attention, including

industry and occupation coding, State

and country coding, and other (specify)

coding.

Industry and occupation coding

A well-developed and tested

computer-assisted coding and quality

control system was used to code

industry and occupation data. Coding

files were created by extracting the

occupation and industry data from the

completed interviews. Spanish industry

and occupation data were translated into

English and inserted into the coding

database, replacing the Spanish text

responses. Using a computer terminal,

coders accessed these coding files and

independently coded each record.

Each occupation/industry record

received two independent codings. If the

two independent coders assigned the

same code, the system accepted the code

as final. If the coders disagreed, the

record was assigned to a third coder for

adjudication. The third coder, considered

to be an expert coder, assigned a code

independently. If the code the

adjudicator assigned agreed with either

of the first two codes, it was accepted as

final. If the code disagreed with both of

the first two codes, the system alerted

the adjudicator to the three-way

disagreement and displayed the codes

assigned by the first two coders. The

adjudicator then entered his or her code,

which was accepted as final.

State and country data

Place of birth, 1990 address, 1993

NHIS-reported address, and 1995

NSFG-reported address were all asked

on the NSFG and had to be coded.

These entries were automatically

assigned three-digit codes during

machine edit by creating a database of

State and country data, writing a

program that matched the alphabetic

entry to a table of acceptable entries,

and assigning the appropriate numerical

code. Data that could not be coded

during machine edit were forwarded to

NCHS staff for resolution. The

resolutions were implemented by adding

entries to the table and re-running the

software or manually entering the

NCHS-assigned code in the data file.

Other (specify) coding

Some questions have several

predetermined categories, and an ‘‘other

(specify)’’ category for responses that do

not fit into one of the predetermined

categories. The answers in these ‘‘other

(specify)’’ questions are typed verbatim

by the interviewer. All specified ‘‘other’’

responses were extracted from the

NSFG data and examined through a

series of machine and manual

operations. Initially, each response was

examined to determine if it matched one

of the precoded responses for the

associated question. These machine

matches included words or phrases with

Series 1, No. 36 [ Page 35
similar meanings, misspelled words, and

brand names. If the ‘‘other’’ entry

belonged in one of the precoded

categories, the code was entered into the

file automatically.

Following this initial step, the

remaining ‘‘other’’ responses for each

question were examined by coding staff

and by the Family Growth Survey

Branch. Similar responses for each

question were grouped together and the

individual responses within each

grouping were tallied. The process of

coding the ‘‘other’’ response data

sometimes affected the answers to

subsequent questions. This resulted in

some additional editing of the data in

order to ensure that the ‘‘other’’

responses were consistent with the

responses to other questions.

A total of 32,000 ‘‘other (specify)’’

entries were reviewed in completing this

coding process. Additional codes were

created if a question had five or more

similar ‘‘other (specify)’’ responses.

Data File Creation

The Cycle 4 Public Use File

documentation was a starting point for

discussions concerning the Cycle 5 data

file layout and documentation. As a

result of these discussions, it was

decided that it would be most cost

effective to use CODEOUT, the program

used in Cycle 4, to produce the Cycle 5

Public Use File documentation.

CODEOUT, developed by NCHS,

produces final codebook documentation

by merging text input with data and

generating formatted text and frequency

distributions for all variables. The input

for the CODEOUT program included

the text of each question, variable

names, column numbers, response

categories, and ‘‘inapplicable

specifications’’ (descriptions of which

respondents were not asked that

question because it did not apply to

them).

The next step was to decide the

basic layout of the data files and the

specific variables to be included in the

files. The basic layouts of the files are

as follows.

Data for the Woman, Also Called the

‘Respondent’ File:

+ Interview data

+ Recoded variables

+ Imputation flags (indicates whether

the value of another variable was

imputed)

+ Weights

+ Time stamps (these show how long

each part of the questionnaire takes)

+ Characteristics of the interviewer

+ Information from the 1993 NHIS

interview

+ Selected data for each of her

pregnancies

+ Pregnancy data from Sections B and

E

+ Recoded variables

+ Weights

+ Imputation flags

Pregnancy Interval File (one record per

pregnancy):

+ Interview data from Sections B and E

+ Recoded variables

+ Weights

+ Imputation flags

NCHS selected the variables to be

included in the data files by reviewing

the complete codebooks. New

codebooks were created for the selected

variables and programs were written to

create the data files directly from the

updated codebooks.

In case manual editing was

required, it was necessary to maintain

Blaise-compatible data files. This

resulted in a sequence of several steps

that had to be repeated to create and

deliver each Respondent and Interval

file. To ensure a complete repetition of

these steps each time, the programs

were initiated by a single batch

command procedure.

SAS Respondent and Interval files

were used by the recode staff to

compute recoded variables and imputed

values. The recode and imputation data

were then merged with the files created

in the previous steps to create the data

files delivered to NCHS. After the data

files were created, they were copied to

tape for shipment to NCHS.

Data File Documentation

Throughout this study, the CRQ

was the primary source of

documentation for the respondent and

pregnancy data from all sections. It

defined all of the questions, answers,

edit checks, and flow checks. As part of

data file documentation, the CRQ was

reviewed and updated to reflect the final

files. The CRQ was then used to

produce representative question text and

‘‘inapplicable specifications.’’

To produce the inapplicable text,

each flow check in the CRQ, explicit or

implied by a ‘‘go to’’ (that is, routing)

response, was applied to each affected

question.

Having accurate inapplicable

specifications is very helpful for data

users, but writing inapplicable

specifications was a tedious,

time-consuming process. A write-andreview process was used in an attempt

to ensure accuracy. Two staff members

who were knowledgeable about the

CRQ drafted the text of the inapplicable

specifications. A third staff member, also

knowledgeable about the CRQ, reviewed

their work for errors and inconsistencies.

Once the inapplicable text was

completed for a singular occurrence of

each question in the instrument, the text

was reviewed by NCHS and revised.

The text was then duplicated and

customized for questions that are

repeated for each occurrence of an

event.

After the inapplicable text had been

finalized, it was combined with variable

names, file positions, question text,

notes, response category labels, and

CODEOUT-specific syntax. The version

delivered by the contractor was

reviewed several times and edited

thoroughly by NCHS staff before it was

ready for release in the Public Use File

documentation.

Discussion

The Survey Control System,

developed to track each sample case,

worked well and provided data that

were used to monitor the progress of all

Page 36 [ Series 1, No. 36
data collection activities. The one area

of the control system that might be

changed is documenting the advance

tracing activities. Although the control

system was designed to monitor each

advance tracing step, it did not maintain

case-by-case result codes from the

NCOA, Telematch, and postcard

verification steps (the control system did

have case-by-case status information for

the telephone advance tracing step).

While this information would not have

been helpful during data collection, it

would have been useful for studies of

the effectiveness of the various tracing

procedures.

The Field Monitoring System,

which provided reports on the status of

data collection to field supervisors and

central-office and NCHS staff, also

worked well. A status report for each

field interviewer would have been

helpful. Although the interviewers had

reports on the status of each case, they

did not have a summary report for their

entire caseload.

Both the data transmission system

and the e-mail system worked well. The

e-mail system was an efficient means of

communicating with the interviewing

staff.

Although the use of CAPI greatly

facilitated the editing process, editing

would be more effective if:

+ Some edit checks were changed

from ‘‘hard’’ failures to ‘‘soft’’

failures that can be overridden.

+ When a ‘‘soft’’ edit failure is overridden, insert a question that

requires the interviewer to explain

the reason why she is overriding the

edit.

+ Pregnancy and wantedness questions

were asked at the same time, so that

post-processing sorting and

matching of pregnancies would not

be necessary.

+ Results from Cycle 5 were used to

develop more precoded responses

for some questions. This would

avoid the additional editing caused

by some other (specify) responses.

+ State and country coding were done

during the interview to eliminate

post-processing.

Finally, the inapplicable

specifications could be developed during

the development of the CRQ, or shortly

after the CRQ specifications are

finished.

References

1. Mosher WD, Bachrach CA.

Understanding U.S. fertility: Continuity

and change in the National Survey of

Family Growth, 1988–95. Fam Plann

Perspect 28(1):4–12. 1996.

2. Mosher WD. Fertility and family

planning in the United States: Insights

from the National Survey of Family

Growth. Fam Plann Perspect

20(5):207–17. 1988.

3. Ventura SJ, Taffel SM, Mosher WD,

Wilson JB, Henshaw S. Trends in

pregnancies and pregnancy rates:

Estimates for the United States,

1980–92. Monthly vital statistics report;

vol 43 no. 11, supp. Hyattsville,

Maryland: National Center for Health

Statistics. 1995.

4. Mosher WD, Pratt WF, Duffer AP.

CAPI, event histories, and incentives in

the NSFG Cycle 5 Pretest. In:

American Statistical Association

(editor), 1994 Proceedings of the

Section on Survey Research Methods,

pp. 59–63.

5. Lessler JT, Weeks MF, O’Reilly JM.

Results from the National Survey of

Family Growth Cycle 5 Pretest. In:

American Statistical Association

(editor), 1994 Proceedings of the

Section on Survey Research Methods,

pp. 64–70.

6. Duffer AP, Lessler J, Weeks MF,

Mosher W. Effects of incentive

payments on response rates and field

costs in a pretest of a national CAPI

survey, in American Statistical

Association (editor), 1994 Proceedings

of the Section on Survey Research

Methods, pp. 1386–91.

7. Mosher WD, McNally JW.

Contraceptive use at first premarital

intercourse: United States, 1965–88.

Fam Plann Perspect 23(3):108–16.

1991.

8. Brewster KL. Neighborhood context

and the transition to sexual activity

among young black women.

Demography 31(4):603–14. 1994.

9. Special issue on confidentiality and

data access. J Official Stat

9(2):269–607. 1993.

10. Jones EF, Forrest JF. Underreporting of

abortion in surveys of US women:

1976–88. Demography 29(1):113–26.

1992.

11. Jones EF, Forrest JF. Contraceptive

failure rates based on the 1988 National

Survey of Family Growth. Fam Plann

Perspect 24(1):12–9. 1992.

12. Tourangeau R, Jobe JB, Pratt WF,

Rasinski K. Design and results of the

women’s health study. In: American

Statistical Association (editor), 1994

Proceedings of the Section on Survey

Research Methods, pp. 49–58.

13. London K, Peterson L, Piccinino L.

The National Survey of Family

Growth: Principal source of statistics

on unintended pregnancy. In: Brown

SS, Eisenberg L, eds. The best

intentions: Unintended pregnancy and

the well-being of children and families.

Washington, D.C.: National Academy

Press. 1995.

14. Moore KA, Nord CW, Peterson JL.

Nonvoluntary sexual activity among

adolescents. Fam Plann Perspect

21(3):110–4.

15. Guadagno MA, Abma JC, Chandra A,

Peterson LS, Piccinino LJ. Women’s

reports of sensitive health conditions,

additudes, and behaviors. In: American

Statistical Association (editor), 1994.

Proceedings of the Government

Statistics Section, pp. 82–7. Alexandria,

VA: American Statistical Association.

16. Potter FJ, Iannachione VG, Mosher

WD, Mason RE, Kavee JD. Sampling

weights, Imputation, and Variance

Estimation in the 1995 National Survey

of Family Growth. National Center for

Health Statistics. Vital Health Stat

2(124). 1997.

17. Chromy JR. Sequential sample

selection methods. In: American

Statistical Association (editor), 1979.

Proceedings of the Section on Survey

Research Methods, pp. 401–6.

Alexandria, VA: American Statistical

Association.

18. Judkins DR, Mosher WD, Botman S.

National Survey of Family Growth:

Design, estimation and inference.

National Center for Health Statistics.

Vital Health Stat 2(109). 1991.

19. U.S. Bureau of the Census. Statistical

Abstract of the United States: 1996

(116th ed). Washington, D.C. 1996.

Especially table 33.

20. Lessler JT, Tourangeau R, Salter W.

Questionnaire design in the cognitive

research laboratory. National Center for

Health Statistics. Vital Health Stat 6(1).

1989.

21. Means B, Nigam A, Zarrow M, Loftus

E, Donaldson M. Autobiographical

memory for health-related events.

Series 1, No. 36 [ Page 37
National Center for Health Statistics.

Vital Health Stat 6(2). 1989.

22. Sudman S, Bradburn NM, Schwarz N.

Thinking about answers: The

application of cognitive processes to

survey methodology. San Francisco:

Jossey-Bass. 1996.

23. Lessler JT. National Survey of Family

Growth Cycle 5 Pretest: Cognitive

appraisal report. 1994.

24. Frost JJ. Family planning clinic

services in the United States, 1994.

Fam Plann Perspect 28(3): 92–100.

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Appendix I

Definitions of Terms

Advance letter—Also called a ‘‘lead

letter.’’ In the NSFG, a letter was sent to

women in the sample (sample women)

explaining the purpose of the study and

how important it was for them to

participate. The letter was sent before

the interviewer contacted the sample

women. Examples of the advance letters

used in the NSFG are shown in

appendix III.

Audio Computer-Assisted

Self-Interviewing (Audio CASI)—A

procedure for administering a

self-administered interview with a laptop

or notebook computer. The respondent

can either read the questions off the

computer screen or hear the

pre-recorded questions through

headphones. This allows the respondent

to hear and answer the questions

without concern that either other family

members or the interviewer will hear

either the questions or her answers. This

technique was used for Section J of the

1995 NSFG questionnaire.

Blaise—A computer-assisted personal

interviewing (CAPI) system developed

by the Netherlands Central Bureau of

Statistics. Blaise was chosen in part

because it handled ‘‘rosters,’’ or event

histories, better than most other CAPI

systems at the time the choice was made

(late 1992). Version 2.5 of Blaise was

used to program the pretest and main

study questionnaires for the NSFG.

Later versions of the program are now

available.

CAPI reference questionnaire

(CRQ)—A document that specifies in

writing everything that CAPI

programmers need to know to write the

program code for the NSFG

questionnaire. This includes all of the

questions; the answer categories that are

allowable; the edit checks, which check

to see if answers are consistent; and the

flow checks, which specify when

questions should be skipped. Example

pages from the CRQ are shown in

figure 3.

Century month—a simple numerical

notation to allow data users to do

arithmetic with dates. The century

month is computed by multiplying the

last 2 digits of the year by 12 and

adding the number of the month, where

January = 1, February = 2, etc. For

example, January 1900 is 001. January

2000 will be (100 x 12)+1= 1201.

May 1970 is (70x12)+5= 845, and

January 1989 is (89x12)+1= 1,069 so

the difference is 1,069–845 = 224. The

dates in the NSFG data file are

expressed in century months.

Cognitive appraisal—A specialized type

of content analysis of a questionnaire

that attempts to describe the task that

survey questions give to a survey

respondent. The framework used for the

NSFG considered what the question

requires the respondent to do in order to

(a) understand the question; (b) retrieve

the information the question asks for;

(c) judge what information meets the

requirements, definitions, and time

periods asked for; and (d) formulate a

response that is in the format asked for.

This kind of framework helps to identify

characteristics of survey questions that

make it difficult for respondents to

answer survey questions accurately.

Cognitive appraisals were used to

improve the NSFG questionnaire (22).

Computer-Assisted Personal

Interviewing (CAPI)—In the 1995

NSFG, a CAPI program was installed

on a laptop, or notebook, computer to

perform a personal interview in the

respondent’s home.

Contextual data—In the NSFG,

contextual data are intended to measure

the ‘‘context,’’ or environment, in which

a survey respondent lives. Many

behavioral scientists want to measure

the effects of State or local government

policies, characteristics of labor markets,

or the characteristics of neighborhoods,

on behaviors such as teenage pregnancy,

marriage and divorce, or use of

contraception. To measure these

concepts, contextual variables in the

NSFG were measured at the State,

county, census tract, and/or block group

levels. Contextual data were obtained

from sources other than the NSFG,

including the 1990 U.S. Census, the

Area Resource Files, disease

surveillance reports from the Centers for

Disease Control and Prevention, and

others.

Disposition codes—A 2-digit numerical

code used in the Field Reports System

that shows what happened to each of the

14,000 cases in the NSFG sample.

Examples of the codes include:

completed interview; sample woman

refused; parent refused; unable to locate;

etc. Table B and the tables in appendix

IX list the final disposition codes. A

comparable set of temporary, or

‘‘pending,’’ codes was used to give the

temporary status of each case. The

temporary code could be changed after

further work or new information about

the case.

Event history—A list of all of the

occurrences of some event, with

beginning and ending dates of each

occurrence, and other significant details.

For example, a marriage history is a list

of all marriages a respondent has had,

with the beginning and ending dates of

each marriage, how it ended (divorce or

death of spouse), and any other details

that are deemed significant. The 1995

NSFG contains event histories of all

marriages, all pregnancies, all periods of

employment and unemployment, all

periods of schooling, etc.

Field interviewer—An interviewer who

does interviews in the ‘‘field,’’ that is,

wherever the respondents are. In

contrast, most telephone interviewers

conduct their interviews from a

telephone center at a headquarters office.

The NSFG interviews were done in the

field, that is, in the respondents’ homes,

by about 260 field interviewers, for an

average of 40 completed interviews per

interviewer.

Field staff—Field interviewers and field

supervisors.

Field supervisor—The direct supervisor

of the field interviewers. In the 1995

NSFG, 15 field supervisors were used,

and each field supervisor was

responsible for about 15–20 field

interviewers. Field supervisors lived in

the territories they supervised. Field

supervisors met by phone with each

interviewer each week during the data

Series 1, No. 36 [ Page 39
collection period to review the

interviewer’s progress, analyze

problems, and offer advice. Field

supervisors also answered urgent

questions whenever needed and helped

train their interviewers at interviewer

training. The 15 field supervisors

reported to 3 regional supervisors

located in the contractor’s home office.

Foxpro—A ‘‘relational database

management’’ software system used in

the NSFG for (a) programming the

month-by-month contraceptive method

calendar in the 1993 pretest, and (b) the

interview ‘‘driver program’’ used in both

the pretest and the main study. Foxpro

Version 2.0 for DOS was used in the

NSFG, although a more recent version

is available at this writing. The current

owner of Foxpro is the Microsoft

Corporation.

Interview Driver program—A program,

written in Foxpro, that connected and

managed the Blaise programs in the

CAPI questionnaire. The Interview

Driver program checked to see that the

interviewer had entered the correct case

identification number before beginning

the interview. The questionnaire was

larger than Blaise version 2.5 could

handle in one unit, so the CAPI program

was split into nine programming units

for the main study (Sections A, B, C, D,

E, F–H, I, J, and K). The Driver

program’s principal function, then, was

to conserve computer memory by

closing out each questionnaire section as

it was completed, and open up the next

section. It also closed out the interview

and identification number when the

interview was completed, so that the ID

number could not be reused by mistake.

Interval file—The part of the NSFG

data file that contains the data on each

pregnancy the woman reported. A

woman would have no pregnancy

‘‘interval’’ records if she had never been

pregnant; in contrast, if she reported 15

pregnancies, she will have 15 pregnancy

‘‘interval’’ records.

Lead letter—See advance letter.

Life history calendar—An 11-inch by

17-inch paper form (appendix VII) used

during the NSFG interview to help the

respondent recall the dates of events.

The interview began by recording

several easily remembered events (for

example, dates of high school

graduation, the births of children, the

date of the first marriage, the death of a

parent). As each additional set of dates

and events were recorded, the events

already recorded served as references to

help the respondent locate the new

events (for example, the dates when a

given contraceptive method was used).

Locator information—In the 1995

NSFG, locator information was

information used to find a new address

or telephone number for women who

had moved since their household was

interviewed in the 1993 NHIS. Locator

information was used only by survey

staff to contact the sample woman to

ask her for an interview. Items of

locator information included the sample

woman’s name, date of birth, Social

Security number, race, and marital

status; and the names, addresses, and

telephone numbers of two friends or

relatives who would be likely to know

how to contact her if she moved. In

other studies, different items might be

useful as locator information.

Looping questions—Questions that are

repeated for each occurrence of an

event. Examples are questions asked

about each man the woman ever

married, or questions asked for each live

birth she had.

The National Center for Health

Statistics (NCHS)—NCHS is the

nation’s principal health statistics

agency. It designs, develops, and

maintains a number of data systems

related to demographic and health

concerns. These include data on

registered births and deaths, the National

Health Interview Survey (NHIS), the

National Health and Nutrition

Examination Survey (NHANES), the

National Health Care Survey, and the

National Survey of Family Growth

(NSFG), among others. NCHS has

conducted the NSFG since 1973. NCHS

is one of the ‘‘Centers’’ of the U.S.

Centers for Disease Control and

Prevention, which is part of the U.S.

Department of Health and Human

Services.

The National Change of Address

system (NCOA)—A service run by the

U.S. Postal Service that helps to update

addresses by identifying persons who

have filed change of address cards with

their post office. The system is an

inexpensive way to identify some

movers, but it does not identify those

who still pick up their mail at the old

address and those who did not file a

change of address notice with the

postmaster.

The National Health Interview Survey

(NHIS)—The NHIS is a principal

source of information on the health of

the civilian noninstitutionalized

population of the United States. The

survey, conducted annually since 1957,

collects information from approximately

43,000 households and 110,000 people

each year on health status, access to

health care and insurance, health

services utilization, health-related

behavior and other topics. The survey

consists of a set of core data items that

are repeated each year and a set of

supplements that can change each year

to address current health topics.

Households interviewed in the 1993

NHIS were used as the sampling frame

for the 1995 NSFG.

Other (specify) coding—Coding of

responses to questions that did not fit in

the prespecified categories of a question.

In the 1995 NSFG, this was done by

examining a list of responses that were

coded by interviewers as not fitting the

prespecified categories and classifying

them as (a) fitting one of the

prespecified categories, (b) fitting one of

the newly specified categories, or (c) as

‘‘other’’ (not specified) responses.

Paired mock interview—A technique

used at field interviewer training for the

NSFG. The trainees use prewritten

interview scripts, which are carefully

designed to cover situations that

typically arise in interviewing.

Interviewers form pairs; one

interviewer-trainee plays the role of the

respondent while the other plays the role

of interviewer. On the next paired mock,

the trainees switch roles, so that both

get to practice interviewing and both see

the point of view of the respondent.

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Primary sampling unit (PSU)—A unit

that is used for the first, or primary,

stage of sampling. (Secondary units are

part of primary sampling units and

tertiary units are part of secondary

units.) In the NHIS and NSFG, a PSU is

a county, a group of contiguous

counties, or a Metropolitan Statistical

Area. 198 PSU’s were selected for the

NHIS. The 1995 NSFG used all 198 of

these areas.

Race/ethnicity—In the 1993 NHIS, the

following categories of race/ethnicity

were collected: Hispanic origin (several

types, including Mexican-American,

Cuban, Puerto Rican, and others); white,

black, American Indian, and 12

categories of Asian and Pacific Islander.

The NSFG does not have enough

sample cases of Asian-Pacific Islander

or American Indian women to analyze

separately, so they are shown in the

‘‘Other race’’ category.

Only three race/ethnicity categories,

however, were used to design and select

the NSFG sample: Hispanic,

Non-Hispanic black, and Other.

Hispanic women and non-Hispanic

black women were sampled at higher

rates than others in the 1995 NSFG in

order to obtain adequate numbers of

Hispanic and black women for analysis.

Thus, when this report contains tables

showing ‘‘race/ethnicity,’’ the three

categories are those used to select

women for the NSFG sample. In reports

that are designed to present substantive

results, the ‘‘other’’ category will be

split into ‘‘non-Hispanic white’’ and

‘‘non-Hispanic other race’’ categories.

Respondents—Persons who answer, or

respond to, a survey. In the 1995 NSFG,

the ‘‘respondents’’ were the 10,847

women who completed the interviews.

The Research Triangle Institute

(RTI)—Located in Research Triangle

Park, North Carolina, RTI was the

contractor selected to conduct the 1995

NSFG. RTI is an independent, notfor-profit organization that serves

government and industry clients in the

U.S. and abroad. RTI conducts research

in public health, medicine,

environmental protection, advanced

technologies, and public policy.

Scientific disciplines at RTI include

applied statistics, social sciences,

environmental sciences, electronics,

physical sciences, engineering,

chemistry, and life sciences. RTI was

established in 1958.

Round-robin interview—A classroom

technique used in NSFG interviewer

training. A group of 15–20 interviewer

trainees go through a carefully written

scripted interview, with the trainer

acting as respondent and the trainees

taking turns asking the questions and

entering the responses into their

notebook computers.

Sample women—The 13,795 women

born between April 1, 1950 and March

31, 1980 who were selected to be in the

1995 NSFG sample. About 79 percent

(10,847) of these women agreed to be

interviewed; they are called

‘‘respondents’’ in this report. However,

about 21 percent were not interviewed,

because they refused, or could not be

located, or were not found at home after

repeated contacts.

Statistical Analysis System (SAS)—A

software package that does data

management as well as statistical

analysis, SAS was used to write the

programs used to create the ‘‘Recoded’’

variables, produce tabulations of results

for editing, consistency checking, and

preparing documentation of the file.

Think-aloud interviews—A technique in

which a respondent is asked to describe

‘‘out loud’’ what she was thinking as

she answered a question. This is thought

to give insight into how respondents

interpret and understand questions, and

what kinds of strategies they use to

arrive at responses. Also called

talk-aloud interviews (22). These were

used in the RTI and NCHS cognitive

laboratories to test NSFG questions.

Series 1, No. 36[ Page 41
Appendix II

Outline of the

Contents of the 1995

NSFG

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Appendix III

Generic Lead Letters

Series 1, No. 36[ Page 57
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Series 1, No. 36 [ Page 59
Appendix IV

Contact Scripts

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Appendix V

Authorization Letter

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Appendix VIII

Field Interviewer

Training Agenda

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Appendix IX

Summary Tables of

Data Collection Status

Reports

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Vital and Health Statistics

series descriptions

SERIES 1. Programs and Collection Procedures—These reports

describe the data collection programs of the National Center

for Health Statistics. They include descriptions of the methods

used to collect and process the data, definitions, and other

material necessary for understanding the data.

SERIES 2. Data Evaluation and Methods Research—These reports

are studies of new statistical methods and include analytical

techniques, objective evaluations of reliability of collected

data, and contributions to statistical theory. These studies also

include experimental tests of new survey methods and

comparisons of U.S. methodology with those of other

countries.

SERIES 3. Analytical and Epidemiological Studies—These reports

present analytical or interpretive studies based on vital and

health statistics. These reports carry the analyses further than

the expository types of reports in the other series.

SERIES 4. Documents and Committee Reports—These are final

reports of major committees concerned with vital and health

statistics and documents such as recommended model vital

registration laws and revised birth and death certificates.

SERIES 5. International Vital and Health Statistics Reports—These

reports are analytical or descriptive reports that compare U.S.

vital and health statistics with those of other countries or

present other international data of relevance to the health

statistics system of the United States.

SERIES 6. Cognition and Survey Measurement—These reports are

from the National Laboratory for Collaborative Research in

Cognition and Survey Measurement. They use methods of

cognitive science to design, evaluate, and test survey

instruments.

SERIES 10. Data From the National Health Interview Survey—These

reports contain statistics on illness; unintentional injuries;

disability; use of hospital, medical, and other health services;

and a wide range of special current health topics covering

many aspects of health behaviors, health status, and health

care utilization. They are based on data collected in a

continuing national household interview survey.

SERIES 11. Data From the National Health Examination Survey, the

National Health and Nutrition Examination Surveys, and

the Hispanic Health and Nutrition Examination Survey—

Data from direct examination, testing, and measurement on

representative samples of the civilian noninstitutionalized

population provide the basis for (1) medically defined total

prevalence of specific diseases or conditions in the United

States and the distributions of the population with respect to

physical, physiological, and psychological characteristics, and

(2) analyses of trends and relationships among various

measurements and between survey periods.

SERIES 12. Data From the Institutionalized Population Surveys—

Discontinued in 1975. Reports from these surveys are

included in Series 13.

SERIES 13. Data From the National Health Care Survey—These

reports contain statistics on health resources and the public’s

use of health care resources including ambulatory, hospital,

and long-term care services based on data collected directly

from health care providers and provider records.

SERIES 14. Data on Health Resources: Manpower and Facilities—

Discontinued in 1990. Reports on the numbers, geographic

distribution, and characteristics of health resources are now

included in Series 13.

SERIES 15. Data From Special Surveys—These reports contain

statistics on health and health-related topics collected in

special surveys that are not part of the continuing data

systems of the National Center for Health Statistics.

SERIES 16. Compilations of Advance Data From Vital and Health

Statistics—Advance Data Reports provide early release of

information from the National Center for Health Statistics’

health and demographic surveys. They are compiled in the

order in which they are published. Some of these releases

may be followed by detailed reports in Series 10–13.

SERIES 20. Data on Mortality—These reports contain statistics on

mortality that are not included in regular, annual, or monthly

reports. Special analyses by cause of death, age, other

demographic variables, and geographic and trend analyses

are included.

SERIES 21. Data on Natality, Marriage, and Divorce—These reports

contain statistics on natality, marriage, and divorce that are

not included in regular, annual, or monthly reports. Special

analyses by health and demographic variables and

geographic and trend analyses are included.

SERIES 22. Data From the National Mortality and Natality Surveys—

Discontinued in 1975. Reports from these sample surveys,

based on vital records, are now published in Series 20 or 21.

SERIES 23. Data From the National Survey of Family Growth—

These reports contain statistics on factors that affect birth

rates, including contraception, infertility, cohabitation,

marriage, divorce, and remarriage; adoption; use of medical

care for family planning and infertility; and related maternal

and infant health topics. These statistics are based on

national surveys of women of childbearing age.

SERIES 24. Compilations of Data on Natality, Mortality, Marriage,

Divorce, and Induced Terminations of Pregnancy—

These include advance reports of births, deaths, marriages,

and divorces based on final data from the National Vital

Statistics System that were published as supplements to the

Monthly Vital Statistics Report (MVSR). These reports provide

highlights and summaries of detailed data subsequently

published in Vital Statistics of the United States. Other

supplements to the MVSR published here provide selected

findings based on final data from the National Vital Statistics

System and may be followed by detailed reports in Series 20

or 21.

For answers to questions about this report or for a list of reports published

in these series, contact:

Data Dissemination Branch

National Center for Health Statistics

Centers for Disease Control and Prevention

6525 Belcrest Road, Room 1064

Hyattsville, MD 20782-2003

(301) 436–8500

E-mail: nchsquery@cdc.gov

Internet: http://www.cdc.gov/nchswww/nchshome.htm
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