DATA EVALUATION

I AND METHODS RESEARCH

National Survey of

Family Growth, Cycle k

Sample Design,

Estimation Procedures, and

VarianceEstimation

●

This report describes the procedures used to select the sample, estimate population parameters, and estimate sampling variances for

Cycle I of the National Survey of Family Growth.

DHEW Publication No, (PHS) 78-1350

Series 2

Number 76

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE

Public Health Service

National Center for Health Statistics s

Hyattsville, Md. January 1978
Library of Congress Cataloging in Publication Data

French, Dwight K.

National survey of family growth, Cycle I.

(Vital and health statistics; Series 2, Data evaluation and methods research; no 76)

(DHEW publication; (PHS) 78-1350)

Includes bibliographical references.

Supt. of Dots. no.: HE 20.6209:2/76

1. Family size–United States–Statistical methods. 2. Fertility, Human. 3. Birth control–United States. I. Title. II. Series: United States. National Center for Health Statistics. Vital and health statistics: Series 2, Data evaluation and methods research; no. 76.

HI. Series, United States Dept. of Health, Education, and Welfare. DHEW publication;

(PHS) 78-1350.

RA409.U45 no. 76 [HQ766.5.U5] 312’.07’23s [301.42’1]

ISBN 0-8406 -0116-6 77-608168

FoL’sale by the Supenntcndent of Documents, L-.S. Govwmmnt Punting office

Washington, D.C. 20}02

Stock X“O. 017-022-00604-!/
NATIONAL CENTER FOR HEALTH STATISTICS

DOROTHY P. RICE, Director

ROBERT A. ISRAEL, Deputy Director

JACOB J. FELDMAN, Ph.D., Associate Director for Andy.sis

GAIL F. FISHER, Associate Director for the Cooperative Health .Stutistics System

ELIJAH L. WHITE, Associate Director for Data Systems

JAMES T. BAIRD, JR., Ph.D., Associate Director for International Statistics

ROBERT C. HUBER, Associate Director for Management

MONROE G. SIRKEN, Ph. D., Associate Director for ~~czthernatical S tatistics

PETER L. HURLEY, Associate Director for Operations

JAMES M. ROBEY, Ph. D., Associate Director for Program Development

PAUL E. LEAVERTON, Ph. D., Associate Director for Research

ALICE HAYWOOD, Information Officer

STATISTICAL METHODS STAFF, DATA SYSTEMS

E. EARL BRYANT, Chief

DIVISION OF VITAL Statistics

JOHN E. PATTERSON, Director

ALICE M. HETZEL, Deputy Director

WILLIAM F. PFuTT, Ph. D., Chiej Family Growth Survey Branch

RITA U. HOFFMAN, Chief Programming Branch

COOPERATION OF THE NATIONAL OPINION RESEARCH CENTER

In accordance with specifications established by the National Center for Hesdth Statistics,

the National Opinion Research Center at the University of Chicago, under a contractrsid agreement, participated in the design and selection of the sample and carried out the data collection.

Vital and Health Statistics-Series 2-No. 76

. DHEW Publication No. (PHS) 78-1350

Library of Congress Catalog Card Number 77-608168
PREFACE

This report presents a detailed description of the sample design, estimation

procedures, and variance estimation method used in Cycle I of the National Survey of Family Growth. The survey was designed and conducted by the National

Opinion Research Center (NORC) of the University of Chicago under a contractual arrangement with the National Center for Health Statistics (NCHS). The

sampling plan was developed under the supervision of Martin Frankel and Benjamin King of NORC, in consultation with E. Earl Bryant, Monroe G. Sirken, and

William F. Pratt of NCHS.

Much of the report, prepared by Dwight K. French of the Statistical Methods

staff, is based upon survey specification documents prepared by NORC and upon

internal NCHS memoranda. Dr. Frankel, Dr. King, Mr. Bryant, and Dr. Pratt,

along with Drs. Gordon Bonham and Dwight Brock of NCHS, were the primary

resource persons for methodological questions.

In addition to internal review, NCHS policy stipulates that methodological

reports are to be given a peer review for technical merit and readabilityy by one or

more persons who are familiar with the subject matter area of the report but are

not involved in producing the report. Mr. Garrie Losee of NCHS carried out the

peer review of this report and made many constructive suggestions.

...

Ill
CONTENTS

Preface ........................................................................................................... ........................................

Introduction ......................................... ...................................... ...... .................. ................ ....................

Design Specifications ..............................................................................................................................

Sample Design ................................................................ ............................................ ............................

Summary ..... ...................................................................................................... ...............................

Determination of Sample Size ......................................... .................... ........................................ ......

Stratification and Selection of PSU’S ......................... ................ ........................ .................. .............

Selection of Second-Stage Units ................................................................ ...... ..................................

Selection of Third-Stage Units .......................................................................................... ................

Selection of Fourth-Stage DwelHng Units .........................................................................................

Fifth-Stage Selection of Sample Persons ...........................................................................................

Characteristics of the Sample .................................................................................................................

Estimation ......................................................................................................... .......................... ...........

Weighting Procedure ...................................................................................................................... ...

Estimating Equation .................................................................................................... .....................

Variance Estimation ..... .... .......................... .................................................................... .. ...... ................

Background ........................................................................................................................ ...............

Summary of Applicable Theory ......... ........................ ........................... ............................................

Application to the NSFG .................................. ...................... .................................... ......................

References .............................................. ................ .................... .................. .................. ........................

Appendixes

L Glossary of Terms .................... ...................................................................... ...........................

II. Evaluation of Alternative Estimators ........................................... ....................................... ......

III. Household Screener ................................................ .... ................ ............................................ ..

LIST OF FIGURES

1.

2.

3.

4.

.

A.

B.

Geographic divisions of the United States, and their order for the first-stage sample ......................

Relative standard errors for aggregates of women, by race ...................................... .......................

Relative standard errors for percent of total and white women (base of percent shown in curve

in thousands) ........................................................... ....................................................................

Relative s~andard errors for mean numbers of births expected by women of afl races and white

women ................................ ............ ................................................ ................ .. .......... .................

LIST OF TEXT TABLES

Standard error tolerances of estimated proportions for selected population subgroups ..................

Sample PSIJ’S for the National Survey of Family Growth ........... .... .. ...................... .......................

...

m

1

1

3

3

3

3

7

8

9

10

11

13

13

14

16

16

16

17

24

26

28

29

4

18

18

21

22

2

5

v
C. Ordering of States for sampling from the National Opinion Research Center non-SMSA frame .....

D. Example of sampling table on the Household Screener ..................................................................

E. Actual and expected number of sample DU’S, number of completed screeners, and screener completion rates, by race and Stratum ...............................................................................................

F. Number of sample women, actual and expected number of completed interviews, and interview

completion rates, by race and Stratum ........................................................................................

G. Screener and interview completion rates and combined response rates, by Stratum .............. .........

H. Comparison of standard error tolerances with the corresponding values obtained from the National Survey of Family Growth (NSFG) .....................................................................................

J. Poststratification adjustment factors (ratio of September 1973 population control totals based

on Current Population Survey data to National Survey of Family Growth weighted estimates),

hy race and age ............................................................................................................................

K. Example of how to determine A& from PSU response data ....................................... .....................

L. Example of a half-sample replication pattern .............. .. .................................. ............ .. .................

M. Estimates of A and B for relative standard error curves, by race .....................................................

SYMBOLS

Data not available ---------------------------------------- ---

Category not applicable -------------------------------- . . .

Quantity zero ---------------------------------------------- -

Quantity more than O but less than 0.05 ------ 0.0

Figure does not meet standards of

reliability or precision (more than

30 percent relative standard error) ----------- *

6

11

12

12

13

13

14

16

17

19

e

vi
NATIONAL SURVEY OF FAMILY GROWTH, CYCLE 1:

SAMPLE DESIGN, ESTIMATION PROCEDURES,

AND VARIANCE ESTIMATION

Dwight K. French, Statistical Methods Staff

INTRODUCTION

The primary mission of the National Center

for Health Statistics (NCHS) is to collect and

publish statistics relating to the health of the

U.S. population. In carrying out its mission,

NCHS collects data on vital events registered in

the united States, conducts inventories of health

facilities and manpower, and conducts probability sample surveys based on household interviews, health examinations, and medical records.

Dtita collection programs are supplemented by

research projects which investigate new techniques of data collection and evaluate currently

operating programs.

In response to the need for current information on the interrelated topics of fertility,

family planning, and their effects on population

growth, the National Survey of Family Growth

(NSFG) was established as an integral part of

the NCHS program in 1972. Since the purpose

of the survey was to collect data relating to

natality and the process of family formation and

dissolution, it was placed within tlie Division of

Vital Statistics. The NSFG is designed as a

cyclic survey; that is, data are to be collected

every few years by means of a sample survey.

The target population for Cycle I of the

NSFG consisted of civilian noninstitutionalized

~vomen living in the conterminom United

States who were less than 45 years of age and

who were currently married, previously married,

or single mothers with children living in the

household at the time of interview. Data were

collected by means of personal interviews with

a probability sample of these women. The interviews furnished information for determining

trends and differentials in fertility, family planning practices, sources of family planning advice

and services, effectiveness and acceptability of

various methods of family planning, and aspects

of maternal and child health that are closely

related to family planning.

The sample design and data collection for

the first cycle of the NSFG were contracted to

the National Opinion Research Center (NORC)

of the University of Chicago. The sample consisted of 10,862 eligible women, of whom 9,800

(90.2 percent) were interviewed during the 8-

month period from July 1973 through February 1974. Other reports will discuss the findings

of the survey. This report describes in detail the

sample design and sample selection procedures

used in Cycle I, the techniques used to estimate -

population parameters, and the procedure used

to estimate sampling variances.

DESiGN SPECIFICATIONS

The development of an efficient Sarilple

design must take into account the primary survey objectives, amount of funds available, logistical problems, time limitations, organized speculation concerning population parameters and

unit operating costs. These requirements dictated a stratified multistage probability sample

design for the NSFG, based essentially on the

following set of specifications:

1, The target population was defined to be

civilian noninstitutionalized women living in the conterminous United States

1
2.

3.

4.

5.

who were less than 45 years of age and

who were either

(a) currently married,

(b) previously married, or

(c) single mothers with one or more of 6“

the children born to them currently

living in the household. 7.

The sample would consist of approximately 10,000 women, selected from an

initial probabilityy- sample of households.

Trained field staff were to conduct a

screening interview with a responsible

member of each sample household to

determine if there were any eligible

women (the screener questionnaire is reproduced in appendix III). When a

household contained one eligible woman, 8.

she was included in the sample. In households with more than one eligible

woman, the staff member would randomly select one woman for the sample. 9.

Data were to be collected from the

sample women by means of personal

interviews lasting an average of 1 hour.

AH interviewers were required to be

female.

The interviewer would collect information on fertility, family planning practices, sources of family planning services,

and related maternal and child health

practices.

The fieldwork would be completed in

approximately 6 months.

The target interview rate for the total

sample and both major subsamples by

race was 90 percent of the expected

number of women from all sample

households (i.e., screener and interview

nonresponse combined would ideally be

no more than 10 percent). Neither

screener nor interview response was supposed to fall below a minimum rate of

90 percent.

The contractor would design and implement procedures to measure and control

the quality of data collection and data

preparation.

For the population subgroups shown in

table A, the sample design should yield

estimated proportions whose standard

errors are within the tolerances given in

the rightmost column. The tolerances

were based on a sample of 3,600 Negro

women and 6,400 women of other races,

and a design factor of approximately 1.4

Tabla A. Standard error tolerances of estimated proportions fors

(that is, it~as assumed ~hat the st~dard

Population subgroup

Negro

.

Education:

Less than high school .......................................................

High school and more ......................................................

Parity:

O-2 children .................. ....................................................

3 children or more ...........................................................

Other races

Education:

Less than high school ...... .................................................

High school and more ......................................................

Parity:

O-2 children ......................................................................

3 children or more ................... .. .................... ..................

Expected proportion

of sample women in

the race group who

are in the subgroup

.48

.52

.50

.50

.30

.70

.59

.41

?cted population subgn

Estimated proportion

within the subgroup

.42

.25

,19

,51

.23

.15

.10

.33

Standard error

tolerance for

estimated proportion

as specified by NCHS

.0164

.0139

.0128

.0163

.0133

.0074

.0068

.0127

2
error of statistics based on the NSFG

design would be about 40 percent larger

than their standard errors based on a

simple random sample of the same size).

SAMPLE DESIGN

Summary

The sample design for Cycle I of the National

Survey of Family Growth (NSFG) was a fivestage probability design based on the National

Opinion Research Center’s (NORC) 1972

Master Probability SampIe.l The counties and

independent cities that make up the total land

area of the conterminous United States were

combined to form a frame of primary sampling

units (PSU’S). From this frame, the first stage of

sampling yielded 203 PSU’S which were divided

into four replicate groups, three containing 51

PSU’S and the fourth having the remaining 50.

Two of these replicate groups, containing 101

PSU’S, were chosen for the NSFG sample. The

next two stages resulted in the selection of several segments (clusters of about 100 dwelling

units) from each sample PSU. A member of the

NORC field staff listed the dwelling units

(DU’s) within each segment, and a fourth-stage

systematic sample of DU’S was selected. At each

sample DU, an NORC interviewer attempted to

complete the Household Screener questionnaire

shown in appendix III and list the names of all

eligible respondents. From this list one eligible

woman was randomly selected for interviewing.

Determination of Sample Size

After the NSFG contract was awarded to

NORC, they agreed to design the sample to produce the race allocation that NCHS suggested in

their precision requirements—3,600 Negro

women and 6,400 women of other races. Once

the allocation was fixed, NORC proceeded to

calculate the number of sample dwelling units

that were needed to produce the final sample

of women, They started by collecting 1970 census information on the number of occupied

DU’S with Negro heads and the number with

heads of other races, as well as population counts

of eligible women in the two race classes. The

ratio of occupied DU’S to eligible women for

both race groups was adjusted to account for

the following three factors:

1.

2.

3.

1970 census data indicated that 8 percent of all DU’S in the United States

were vacant.

Data from the NCHS Health Interview

Survey indicated that 5 percent of all

eligible women lived in households containing two or more eligible women.

Combined screener and interview nonresponse was expected to be 10 percent.

The adjusted DU-person ratios represented

the expected number of DU’S that would have

to be screened in order to find and interview one

sample woman in each race class. By multiplying the final ratios by the desired number of

sample persons, NORC calculated the expected

minimum number of DU’S that wouId need to

be screened to yield 3,600 completed interviews

with Negro women and 6,400 completed interviews with women of other races—9 ,141 Negro

DU’S and 18,091 DU’S of other races, or a total

of 27,232 DU’S.

These minimum numbers of DU’S, however,

do not represent the actual number that were required to be screened for the NSFG. In areas

where a large proportion of the population was

Negro, DU’S were oversampled to attain the required number of Negro women. In order to

keep the sample essentially self-weighting for

women of other races, DU’S of other races were

subsampled in these areas. However, it was

necessary to screen all DU’S in order to determine their race. This subsampling procedure increased the number required to be screened

from the minimum 27,232 to 31,842.

Stratification and Selection of PSU’S

The PSU’S in the NORC master sample were

selected from separate sampling frames of standard metropolitan statistical areas (SMSA’S) and

nonmetropolitan areas in the conterminous

United States. The SMSA frame consisted of

the 246 SMSA’S as defined by the U.S. Bureau

of the Census in March 1971. The frame was

3
ordered in the following manner, based on advance 1970 census population data:

1.

2.

3.

The SMSA’S were first sorted by the nine

census geographic divisions as shown in

figure 1.

Within each geographic division, the

SMSA’S were sorted into three size

classes: 1,000,000 persons or more,

200,000 to 999,999 persons, and less

than 200,000 persons.

In divisions 1, 2, 3, 4, 8, and 9, the

SMSA’S in each size class were sorted by

State, with the States placed in geographic order from northwest to northeast to southeast to southwest. Within

each State the SMSA’S were ordered in

the same way. In divisions 5, 6, and 7,

the SMSA’S in each size class were placed

in descending order of the number of

residents of races other than white, in

order to increase the likelihood of selecting an appropriate number of southern

SMSA’S with large Negro populations.

The total population of the SMSA frame

based on preliminary 1970 census data was

138,789,636. After the ordering was completed,

the frame was divided into 139 sequential zones,

each having 1 million population (the 139th

zone contained 789,636 persons and 310,364

“blanks”). In each zone the numbers from 1 to

1 million were assimed in ordered intervals to

the SMSA’S that were totally or partially included, each SMSA receiving an interval equal

to its population within “the zone. A “hit

number” between 1 and 1 million was randomly

and independently selected for each zone, and

the SMSA whose assigned interval included that

number was the PSU selected to represent the

zone. The selection of a hit number was not

Figure 1. Geographic divisions of the United States, and their order for the first-stage sample

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necessary for zones that were completely covered by one SMSA. This selection procedure

differs somewhat from classical sampling with

probability proportionate to size in that SMSA’S

that overlapped zones could be selected more

than once, and very large SMSA’S had to be

selected several times. For example, the New

York City SMSA represented 11 zones, all of

which it covered completely. It was not selected

to represent two other zones that it did not

cover completely.

After the PSU’S were selected, the 139 zones

were systematically separated into four groups

(zones 1, 5, 9, . . .. 137 constituted group 1;

zones 2, 6, 10,. ... 138 constituted group 2;

etc. ). Groups 1 and 3 were randomly selected,

and the SMSA’S that represented the zones in

those two groups became part of the NSFG

sample. The remaining two groups were held in

reserve, but were not used in the NSFG. The

sample of the SMSA population consisted of 70

Psu’s, containing 56 distinct SMSA’S (see

table B).

All areas in the United States that were not

Table B. Sample PSU’S for the National Survey of Family Growth

SMSA’S

Akron, Ohio

Allentown-Beth lehem-Easton, Pa.-N .J.

Appleton-Oshkosh, Wis.

Atlanta, Ga,

Baltimore, Md.

Birmingham, Ala,

Boston, Mass.

Buffalo, N.Y.

Chicago, IIl. (represented by 4 PSU’S)

Clevelend, Ohio

Columbie, S.C.

Columbus, Ohio

Dallas, Tex,

Denver, Colo.

Des Moines, Iowa

Detroit, Mich. (represented by 2 PSU’S)

Flint, Mich.

Fresno, Calif.

Gary-Hammond-E, Chicago, Ind.

Great Falls, Mont.

Hartford, Corm.

Houston, Tex.

Indianapolis, Ind.

Jersay City, N.J,

Knoxville, Term.

Little Rock-N. Little Rock, Ark.

Los Angales-Long Beach, Calif. (represented by 3 PSU’S)

Miami, Fla,

Minneapolis-St, Paul, Minn.

Nashville, Term,

Naw Britain, Corm.

New Orleans, La.

New York, N,Y. (rapresented by 5 PSU’S)

Newark, N,J. (rapresented by 2 PSU’S)

Norfolk-Virginia Beach-Portsmouth, Va.

Oklehoma City, Okla.

Orlando, Fla.

Pensacola, Fla.

Philadelphia, Pa,-N.J, (represented by 2 PSU’S)

Phoenix, Ariz,

Pittsburgh, Pa,

Portland, Oreg.-Wash.

Racine, Wis.

Reading, Pa.

Rochester, N .Y,

St. Louis, Mo.-l Il. (represented bv 2 PSU’S)

San Bernardino-Rivarsida-Ontario, Calif.

San Diego, Calif.

San FranciscoQakland, Calif. (represented by 2 PSU’S)

Santa Rosa, Calif.

Springfield-Chicopee-Holyoke, Mass.-Conn.

Stamford, Corm.

Tacoma, Wash.

Topeka, Kan.

Washington, D.C.

Wichita Falls, Tex.

Non-SMSA PSU’S

Auglaize Co., Ohio

Burnett Co.-Washburn Co., Wis.

Carroll Co,, Mo.

Columbiana Co., Ohio

Colusa Co., Calif.

Florence Co., S.C.

Gogebic Co., Mich.

Houston Co., Ala.

Iredell Co., N.C.

Knox Co., Ohio

Lincoln Co.-Rock Co., Minn.

Long Branch-Asbury Park, N.J.

Madison Co., S.C.

Manitowoc Co,, Wis.

Marion Co., W. Va.

Marquatte Co,, Mich.

McDowell Co., W. Va.

Meklenburg Co,, Va.

Mesa Co., Colo.

Newaygo Co., Mich.

St. Lucie Co., Fla.

Schuylkill Co., Pa.

Smyth Co., Va.

Sumter Co., Ga.

Sussex Co., N .J.

Upshur Co., W. Va.

Victoria Co., Tex.

Washington Co., Ala.

Wilkes Co., N.C.

Willacy Co., Tex.

Yuba Co., Calif.

5
included in the SMSA frame. can be classified

either as counties, independent cities, or, in New

England, portions of counties (for convenience,

all such areas will hereafter be referred to as

“counties”). In certain instances, sparsely populated counties were linked to provide an adequate population base for later stages of sampling. The non-SMSA frame consisted of the

conterminous United States minus the 246

SMSA’S, with the individual and linked counties

ordered as follows:

1. Counties from census divisions 1 and 2

with 50,000 persons or more, arranged

in descending order of population (DOP).

2. Counties from divisions 3 and 4 with

60,000 persons or more, arranged in

DOP within State. The order of States

for divisions 3 and 4 is given in table C.

3. Counties from divisions 3 and 4 with

populations between 30,000 and 59,999,

where the proportion of the population

living in urban areas (as defined by the

U.S. Census Bureau) “was greater than

or equal to 40 percent, arranged in DOP

within State.

4. Counties from divisions 3 and 4 with

populations less than 30,000, where the

urban proportion was greater than or

equal to 50 percent, arranged in DOP

within State.

5. Counties from divisions 5, 6, and 7 with

populations greater than or equal to

30,000, where the urban proportion was

30 percent or greater and the proportion

of the population that was Negro was

less than 20 percent, arranged in DOP

within State. The order of the States is

given in tabIe C.

6. Counties from divisions 5, 6, and 7 with

populations greater than or equal to

30,000, where the urban proportion was

30 percent or greater and the Negro proportion was 20 percent or greater,

arranged in DOP within State.

7. Counties from division 8 arranged in

DOP.

8.

9,

10.

Counties from division 9 arranged in

DOP.

Counties from divisions 1 and 2 with

populations less than 50,000 arranged

in DOP,

Counties from divisions 3 and 4 with

populations between 30,000 and 59,999,

where the urban proportion was less

than 40 percent, arranged in DOP within

State.

11. Counties from divisions 3 and 4 with

populations less than 30,000, where the

urban proportion was less than 50 percent, arranged in DOP within State.

12. Counties from divisions 5, 6, and 7 with

13.

14.

populations greater than or equal to

30,000, where the urban proportion was

less than 30 percent and the Negro proportion was less than 20 percent, arranged in DOP within State.

Counties from divisions 5, 6, and 7 with

populations less than 30,000, where the

Negro proportion was less than 20 percent, arranged in DOP within State.

Counties from divisions 5, 6, and 7 with

populations greater than or equal to

30,000, where the urban proportion was

less than 30 percent and the Negro proportion was 20 percent or greater, arranged in DOP within State.

Table C. Ordering of States for sampling from the National

Opinion Research Center non-SMSA frame

Area I Order of States

North Central Region

Divisions 3 and 4 ............

South Region

Ohio, Michigan, Wisconsin, Minne.

sotar Indiana, IIlinois, Missouri,

Iowa, Kansas, Nebraska, North Dakota, South Dakota

Delaware, Maryland, West Virginia,

Virginia, Kentucky, Tennessee,

North Carolina, South Carolinar

Divisions 5, 6, and 7.......

Georgia, Alabama, Mississippi,

Louisiana, Arkansas, Floride,Texes,

Oklahoma.

6
15. Counties from divisions 5, 6, and 7 with Selection of Second-Stage Units

populations less than 30,000, where the

Negro proportion was 20 percent or

greater, arranged in DOP within State.

The total population of the non-SMSA

frame based on preliminary 1970 census counts

was 63,456,729. This frame was partitioned in

the same way as the SMSA frame into 64 zones

of 1 miIIion persons (zone 64 contained 543,271

“blanks”). The method of selecting a county to

represent each zone was exactly the same

method used for SMSA’S; however, the method

of determining the primary and reserve PSU’S

was different. The 64 zones were divided into

16 sets of 4 (zones 1-4 formed the first set,

zones 5-8 the second set, and so forth). Each set

of numbers was randomly permuted, and the

counties representing the first two zones in the

sequence were assigned to the NSFG sample.

For example, the permutation of zones 1-4 was

3, 1, 4, 2. Therefore, the counties representing

zones 3 and 1 were included in the survey, while

the remaining two selections were placed in

reserve status. Only 31 PSU’S were selected

from the non-SMSA frame because a blank was

selected as the hit number in zone 64, and zone

64 was listed second in the permutation of set

16. Thus the first-stage non-SMSA sample consisted of 31 counties, none appearing more than

once, These 31 counties, when added to the

ShK3A sample, produced a total first-stage sample of 101 PSU’S from 87 distinct localities.

NORC’S methods of ordering SMSA’S and

non-SMSA counties, selecting PSU’S from zones

of 1 million persons, and subsampling to determine primary and reserve PSU’S ensured a reasonable geographic, racial, and urban-rural

balance among the PSU’S. Even after the preliminary ordering, NORC was concerned that a

sample of four PSU’S from zones of 4 million

persons would result in excessive geographic

clustering. They therefore decided on the more

detailed method of selection from smaller zones.

The systematic group method of selecting primary and reserve SMSA’S was changed to random selection within sets for counties because

the cyclical ordering of the non-SMSA frame

might have caused geographic clustering if systematic sampling had been used.

The units selected in the second stage of

sampling were block groups (BG’s) in areas where

census blocks were delineated and census enumeration districts (ED’s) in other areas, Each of

the 87 distinct localities was completely covered

by a nonoverlapping frame of BG’s, ED’s, or a

combination of the two.

In order to reduce sampling error and ensure

proportionate representation of women by race

and income, the second-stage frame within each

PSU was ordered by these variables prior to

sampling. Because 1970 census income data

were not available at the BG and ED level,

NORC attached to each unit the income and

racial characteristics of the next higher order

census unit, which in most areas was the tract.

In predominantly rural counties that were not

tracted, the minor civil division (MCD ) or census

count y division (CCD ) was the next level unit.

The National Opinion Research Center purchased

from the National Planning Data Corporation of

Ithaca, New York, population and housing data

for ED’s and BG’s, and income and racial composition data for tracts, MCD ‘s, and CCD’S

within each of the 87 distinct localities.

With these data the second-stage frame

within each PSU was ordered in the foIIowing

manner:

1. In SMSA’S the ED’s and BG’s in tracts

with less than 10 percent Negro households were placed before units in tracts

with at least 10 percent Negro households. (For this purpose, the race of the

household was defined as the race of the

head.) Within each race group, the units

were arranged in ascending order of

median tract income. Within each tract

the ED’s and BG’s were arranged in

numerical order, with BG’s preceding

ED’s if both types of unit were present.

2. In non-SMSA PSU’S the above method

of ordering was applied when at least 6

percent of the total population was

Negro. In counties where Negroes constituted less than 6 percent of the population, the tracts, MCD’S, and CCD’S were

either placed in ascending order by

median ‘income or, in sparseiy populated

7
counties, arranged from northwest to

northeast to southeast to southwest.

Within each higher order unit, the BG’s

or ED’s (usually ED’s) were arranged in

numerical order.

After the ED’s and BG’s were ordered, small

units were linked with the unit immediately

following to assure a minimum unit size of 100

DU’S. The cumulative households in each PSU

were then divided into 18 zones of equal size.

Within each of these second-stage zones, the

numbers between 1 and the zone size were

grouped into ordered intervals representing BG’s

and ED’s in the same way that the intervals in

first-stage zones represented SMSA’S and counties. A random hit number was selected for each

zone to determine the ED or BG that would

represent the zone. For SMSA’S that appeared

more than once in the principal sample, this

procedure was carried out for each first-stage

appearance. Thus the Chicago SMSA, with 4 hits

in the sample, was represented by 4 X 18 or 72

second-stage units.

Of the 18 second-stage units associated with

each PSU, a subsample of 12 was selected for

the NSFG. The 18 second-stage units were put

into 6 groups of 3 units apiece (group 1 consisted of ED’s and BG’s from zones 1, 2, and 3;

group 2 included units from zones 4, 5, and 6;

etc.). A random number was independently

selected for each group to determine which

second-stage units were to be eliminated from

the NSFG sample. The second-stage sample now

contained 1,212 second-stage units within the

101 Psu’s.

At this point NORC and NCHS decided to

supplement the sample by selecting additional

second-stage units in areas where the population was largely Negro, because the design requirements of the NSFG dictated an oversampling of Negro females. Without these additional

units later-stage sampling rates in areas with

many Negroes would have been much larger

than the rates in areas with few Negroes. The

resulting large cluster sizes would have greatly

increased the variances of survey estimates.

The first step in selecting the supplemental

sample was to identify all second-stage units in

tracts, MCD’S, and CCD’S with

percent Negro households (again,

at least 10

the race of a

household was determined by the race of its

head). The zones represented by these units

were split into two half zones of equal size,

say z. If the original hit number h for a zone

fell into the first half zone, the number h -!- z

was used to select a tentative supplemental ED

or BG. If the original hit number fell into the

second half zone, h - z was the supplemental hit

number.

The selection procedure had to be modified

for Washington County, Alabama, and Sumter

Count y, Georgia. The 36 original ED’s representing these rural, predominantly Negro PSU’S

encompassed virtually all of their population.

Therefore, it was necessary to return to the firststage non-SMSA zones represented by these

PSU’S and randomly select an additional PSU

from each. The two supplemental PSU’S were

Hale County, Alabama, and Newton County,

Georgia. Their BG’s and ED’s were ordered

according to the procedure described earlier, and

their cumulative DU’S were divided into 12

zones of equal size. The second-stage zone

method was used to select 12 tentative supplemental units from each PSU.

To determine which of the tentative supplemental units would be included in the sample,

each one was paired with its corresponding original selection and the simple average percent of

Negro households was computed for each pair.

It was estimated by NORC that in order to produce the required sample of 3,600 Negro women

with a sample of 32,000 DU’S, the supplemental

unit should be included when the average percent of Negro households was 43.4 or larger.

Otherwise, only the original unit should be retained. The average exceqded 43.4 percent for

122 of the 1,212 zones. Therefore, the NSFG

second stage consisted of 1,090+ 2(122) = 1,334

ED’s and BG’s. For purposes of subsequent

sampling, the units were divided into two Strata.

Stratum I consisted of the 1,090 predominantly

white units from the zones where the supplemental unit was not used. Stratum 11 consisted

of the remaining 122 pairs of units.

Selection of Third-Stage Units

The purpose of the third stage of sampling

was to select from each ED and BG a subarea

called a “segment” containing approximately

8
100 DU’S. When an entire second-stage unit

contained only about 100 DU’S, no third stage

of sampling was required. When a third stage

was necessary, however, the logistics of selecting

a segment from a BG and an ED were quite

different.

The BG is an urban geographic unit introduced during the 1970 census. It consists of a

set of city blocks with the same highest order

digit in the census block identification number.

For the third stage of sampling, NORC subjectively split the BG into groups of blocks, each

group containing approximately 100 DU’S

according to 1970 census counts. One group

was randomly selected with probability proportionate to its size relative to the size of the total

BG.

The ED is a census divisional unit generally

used in nonmetropolitan areas. It is usually

the lowest level unit for which decennial census

information on households is available. In some

instances, however, an area called an “ED” during the second stage was found to be covered by

blocks. When that was the case, any necessary

third-stage sampling was carried out in the manner described in the preceding paragraph. When

blocks were not delineated and the ED had

many more than 100 DU’S, the ED was split

into pseudoblocks which were bounded by roads

and other easily recognizable landmarks. Dwelling units within the pseudoblocks were field

counted in order to get rough measures of size,

and a segment of approximately 100 DU’S was

selected with probability proportional to its size

relative to the size of the entire ED according

to the rough count.

The final third-stage NSFG sample consisted

of 1,334 segments, one corresponding to each

sample BG and ED. Therefore, there were 1,090

segments in Stratum I and 244 in Stratum II.

Selection of Fourth-Stage Dwelling Units

Members of the NORC field staff listed the

DU’S within each of the 1,334 segments. An

independent, systematic sample of DU’S was

selected from the listing sheet for each segment.

The individual fourth-stage sampling rates were

chosen so that the sample of DU’S was essentially self-weighting within Strata. That is, the

overall probabilities of selecting all sample DU’S

in Stratum I were approximately equal, as were

the probabilities associated with sample DU’S

from Stratum II.

In order for NORC to determine the fourthstage sampling rate for each segment, they

first had to determine PI and PII, the uniform

probabilities of selection for the two Strata.

To do this, preliminary census data were used to

estimate the proportion of households in each

Stratum with Negro heads. These proportions,

along with the required number of screened

DU’S for Negroes and persons of other races,

were the constraints used to calculate the required number of screened DU’S for the two

Strata (hereafter denoted by SI and SII). Next,

DT, the number of occupied DU’S in the United

States at the time of the survey, was projected

from census housing totals for 1970 and 1972.

The number of occupied DU’S in the United

States which were in ED’s or BG’s that met the

definition of Stratum I was estimated by

()1,090 D1 = — D=

1,212

where 1,090/ 1,212was the proportion of original second-stage sample units that fell into

Stratum I. A corresponding estimate of occupied DU’S for Stratum II units in the United

States was

()122 D

D1l = —

1,212 ~“

Because 1970 census data indicated that 92 percent of aIl DU’S in the United States were occupied, the selection probabilities for the two

Strata were given by

SI ● 0.92

PI = = .000276219 and

D1

s~1s0.92

P1l =

D1l

= .002207277

Once NORC had calculated PI and PII, the

fourth-stage sampling rate for any segment could

be obtained by dividing PI or P1l by the product

9
of the known probabilities of selection at the

first three stages. The fourth-stage rates yielded

an average of 16.7 screened DU’S per segment in

Stratum I and 56.9 in Stratum II. It’ is obvious

from the difference between these average

cluster sizes that oversampling of ED’s and BG’s

at the second stage could not by itself produce

the required oversimple of Negro women.

Further oversampling of DU’S was necessary

within sample segments.

Because the field listing sheet was the

frame for the fourth-stage sample, DU’S that

were missed during the field listing, or that came

into existence between the time of field Iisting

and interviewing, had zero probability of being

sampled directly. In order to give these DU’S

the same probability of selection as listed DU’S

in their respective segments, NORC developed a

set of rules based on the half-open interval procedure.2 These rules enabled the interviewer

to link each missed DU and each new DU with

exactly one existing line of the segment listing

sheet.

The set of lines for a segment was first divided into subsets that represented listings for

individual blocks. In urban areas blocks were

usually well-defined units, but in many rural

segments “blocks” were of widely varying

shapes and sizes. The only requirements for a

rural block were clearly defined boundaries and

a complete up-to-date listing of DU’S by address

or location. Each line within a block represented a structure or a subunit within a structure

(such as an apartment or room). The listings

were considered circular; that is, the last listing

within a block was “followed” by the first.

When a sample line represented a complete

structure, the interviewer was instructed to complete a screener for any DU’S witbin that structure as well as any DU’S between that structure

and the structure on the next line. “Between”

was defined in terms of address numbers when

they were available, and in terms of location

when they were not. If a sample line represented a subunit within a structure, the interviewer’s instructions depended upon the position

of the sample line relative to the lines representing the other subunits. Since the listings

were ordered, each multiunit structure had a

first- and last-listed subunit and any number

(from O to n) of other subunits. If the sample

line was a first-listed subunit, the interviewer

was instructed to complete a screener for all

additional DU’S within the subunit and a.11DU’S

in the structure that were in unlisted subunits.

If the sample line was a last-listed subunit, the

interviewer was instructed to complete a screener

for all additional DU’S in that subunit and all

DU’S between the structure containing the subunit and the next-listed structure. If the sample

line represented any other subunit, the interviewer was only responsible for additional DU’S

in the subunit.

In order to avoid large increases in sample

size due to additional DU’S, NORC set an arbitrary limit of four DU’S per sample line. If more

than three additional DU’S were associated with

the original sample listing, the interviewer was

instructed to call headquarters, where a random

subsample of exactly four DU’S was chosen to

receive screeners.

The procedures for listing additional DU’S

and subsampling excess DU’S added 780 unlisted

DU’S to the original sample, of which 439 were

in Stratum I and 341 were in Stratum H. The

subsampled DU’S were exceptions to the principle of- equal probability if selection within

Strata.

Additional exceptions to equal probability

of selection were made for 10 segments in

Stratum I which had grown rapidly from the

time of the census DU count to the time of the

NORC field listing. The field staff in these

“fast-growth” segments returned their listing

sheets to NORC’S central office. The central

office reduced the fourth-stage sampling rates

to keep the number of sample DU’S from exceeding 50, so that the interviewer’s workload

would not become overly burdensome,

Fifth-Stage Selection of Sample Persons

To avoid the high correlation of information

from eligible women within the same DU, the

NSFG design stipulated that no more than one

eligible woman from any sample DU would be

interviewed. During completion of the Household Screener, the NORC interviewer listed all

members of the DU on the second page of the

form and relisted the eligible females in order

of age in item 13 on the third page (see appendix

III). Item 13 provides space for listing up to six
persons because six was considered to be a reasonable limit for the number of eligible females

to be expected from a single DU. When the

interviewer listed more than one eligible female

she referred to the sampling table on the first

page of the questionnaire to determine the person she was supposed to interview. The sampling

table consists of five numbers that designate

which, person to interview when the number of

eligible females is two, three, four, five, or six

(see table D). National Opinion Research Center personnel filled in the table on every Household Screener by randomly ordering the 720

possible sets of numbers and systematically

assigning them to screeners. This method of

assigning interviews gave each eligible woman in

a given DU the same probability of being

selected.

The oversampling in Stratum II at the second and fourth stages of selection led to the

desired oversampling of Negro females at the

fifth stage, However, since 35 percent of the

DU’S in Stratum II were expected to be of other

races, oversampling would also have produced

an unnecessarily large sample of females of other

races. NORC avoided that costly problem by

subsampling DU’S of other races at a rate of 1

out of 7.991. This rate gave the subsampled

DU’S the same probability of selection as all

DU’S in Stratum I. Subsampling was accomplished by systematically printing “interview

regardless of race” on 1 of every 7.991 screeners

used in Stratum II and “interview if Negro only”

on the rest. For this purpose, the race of a DU

was defined as the race of the person who provided the information for the Household

Table D. Example of sampling table on the Household Screener

IF NUNSER OF THEN INTERVIEW

ELIGIBLE FEkL4LES PERSON USTEO

LISTED IN SUM- ON SIJWU,RiEOX

ILN+YBOX IS: LINE

J $$.

El

Two

Three 3

/

Four I

Five +

Six or

more z

Screener because it seemed likely that the

screener respondent would often be an eligible

respondent for the survey and because it might

have been difficult to determine the race of all

household members in some instances.

CHARACTERISTICS OF THE SAMPLE

The first four stages of the design resulted in

the identification of 32,818 sample DU’S. During the screening process, the interviewers discovered that 3,820 of these either were vacant

or did not meet the definition of a DU. Complete Household Screeners were obtained for

26,028 of the remaining 28,998 occupied DU’S,

for a screener completion rate of 89.8 percent

(table E). After 2,674 DU’S were removed from

the sample by the subsampling procedure in

Stratum II, the final sample of 23,354 DU’S

yielded a fifth-stage sample of 10,879 women,

of which 4,362 were Negro and 6,517 were of

other races (table F). Complete interviews were

obtained for 9,817 women, of which 3,868 were

Negro and 5,949 were of other races, for an

interview completion rate of 90.2 percent (88.7

percent for Negro women and 91.3 percent for

women of other races). Combined screener and

interview response rates cannot be computed by

race because the race of the majority of nonresponding DU’S was unknown. Combined

screener and interview response by Stratum is

shown in table G.

Seventeen women (10 Negro, 7 of other

races) were eliminated from the sample after

they were interviewed because it was discovered

that they had passed their 45th birthday before

the date of interview. In addition, data for three

sample women who were less than 15 years of

age (two Negro, one of another race) were excluded from all tabulations so that analysis

could be conducted for eligible women 15-44

years of age. Therefore, NSFG estimates are

based upon data from 9,797 women, of which

3,856 are Negro and 5,941 are of other races.

While the number of interviewed Ne,gro

women exceeded the desired sample size ‘of

3,600, the number of interviewed women of

other races fell substantially short of the target

of 6,400. Most of the additional Negro sampIe

was due to the unexpectedly large number-of

11
Table E. Actual and expected number of sample DU’S, number of completed screeners. and screener comrJetion rates. bv race and Stratum

Expected

number of

legitimate.

occupied

D U’s from

presurvey

estimates

(4)

29,295

Number of

DU’S for Screener

which a

completion

complete ratel

screener was (percent) obtained

Total DU’S Number of

Vacant or legitimate, in the

sample not a DU occupied

DU’S Race and Stratum

All races

Both Strata ....................................................................

Stratum I .......................................................................................

Stratum 11......................................................................................

Negro

Both Strata ....................................................................

Stratum I .......................................................................................

Stratum 11......................................................................................

Other races

Both Strata ....................................................................

Stratum I .......................................................................................

Stratum 11......................................................................................

32,918 I

3,820 I

228,998 226,028 I 89.8

18,593 2,038 216,555

14,225 1,782 212,443

. . . . . . 9,005

*15,134 91.4

210,894 87.6

9,548 3

. . .

16,576

12,719

B,41O

. . . . . . 773

. . . . . . 8,232

. . . . . 18,438

656

7,754

20,885

725 3

.,.

7,821 3

.,.

17,328 3

,..

. . .

I

...

I

15,059

. . . . . . 3,379

74,278 3

. . .

3,050 3. . .

15,920

4,965

q(s)+ (3)] x 100.

?Inclrrdes race unknown.

3Appropriate screener completion rates by race cannot be derived because race information was not available for all legitimate, occupied DU‘s.

Table F. Number of sample women, actual and expected number of completed interviews, and interview completion rates, by race and Stratum

Race and Stratum

Number of

sample

women

(1)

Number of

completed

interviews

(2)

Interview

completion

rate 1

(percent)

(3)

Approximate

number of

completed

interviews

expected

from

presurvey

estimatas

(4)

All races

8oth Strata ............................................................................................................. 10,879 9,817 90.2 10,054

6,758

4,121

4,362

394

3,968

6,517

6,364

153

26,451

3,600

6,164

3,653

3,86B

341

3,527

5,949

5,823

126

91.2

88.6

8B.7

86,5

88.9

91.3

Negro

Both Strata ............................................................................................................. 3,600

281

3,319

Other races

Both Strata ............................................................................................................. 26,454

6,173

291

91.5

82.4

1[(2) +(1)] x 100.

2The target SampIc size f~)r women of ~aces other tlmn Negro was 6,400. However. the assigned probabilities of SekCtiOn fOr DU”Sof race Other than

Negro in Stratum 1 and Stratum 11 yielded a slightly larger expected sample size thmr the original target.
Table G. Screener and interview completion rates and combined

response rates, by Stratum

Screener Interview

comple- Combined

Stratum completion tion response

rate rate ratel

(1) (2) (3)

I

Percent

Both Strata ......... 89.8 90.2 81.0

Stratum I ....................... 91.4 91.2 83.4

Stratum II m.................... 87.6 88.6 77.6

~[(1) x (2)] + 100.

Negro DU’S identified in Stratum II (table E).

This oversimple was enough to overcome the

higher-than-expected vacancy and nonresponse

rates. The number of DU’S of race other than

Negro in Stratum II was correspondingly much

lower than expected. However, because of the

subsampling procedure the number of interviewed women of races other than Negro was

only 155 less than expected, In Stratum I the

number of identified DU’S was also somewhat

less than the expected value, and the vacancy

and interview nonresponse rates were higher

than expected. These problems caused the remaining sampling deficit for women of races

other than Negro, but had little effect on the

size of the Necgro sample because less than 5 percent of the DU’S in Stratum I were classified as

Negro.

Table H shows that the precision of survey

estimates was not adversely affected because the

target number of women of races other than

Negro was not interviewed. Standard errors for

the estimated proportions in table A were calculated from NSFG data using the balanced

half-sample replication technique described later

in this report. For all population subgroups

except Negro women of parity 3 or more, these

standard error estimates are substantially lower

than the corresponding presurvey error tolerance. The estimate for higher panty Negro

women is slightly larger than its tolerance, but

the difference is unimportant, since the variance

estimates themselves are subject to variance.

ESTIMATION

Weighting Procedure

Since the NSFG is designed to produce unbiased estimates for the entire population of

Table H. Comparison of standard arror tolerances with the corresponding values obtained from the National Survey of Family

Growth (NSFG)

Population subgroup

Nagro

Education:

Lass than high school ........................................................................

High school and mora .......................................................................

Parity:

O-2 children ....................................................... ................................

3 children or more ............................................................................

Other races

Education:

Less than high school . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

High school and more .......................................................................

Parity:

0.2 children . ... ... .. .. ... .. ... .. .. ... .. .. ... .. .. .. . ... .. .. ... .. ... . ... .. .. ... . .. ... .. .. ... .. .. ...

3 children or more .................................................................. ..........

Proportion of

women in the rata

group who are in

the subgroup

From

table A

.48

.52

.50

.50

.30

.70

,59

.41

NSFG

astimate

.48

.52

.58

.42

.27

.73

.64

.36

Estimated

proportion

within the

subgroup

.42

.25

.19

.51

.23

.15

.10

.33

Standard

error

tolerance

from

table A

.0164

.0139

.0128

.0163

.0133

.0074

.0068

.0127

Estimated .

standard

error

basad on

NSFG data

.0150

.0121

.0112

.0170

.0106

.0053

.0054

.0099

13
eligible women in the United States, the sample

data must be inflated to the level of the population from which the sample was drawn. The inflation factor, or weight, for each woman is

the product of several adjustments, one or more

at each stage of sampling. Three types of adjustments are involved.

Inflation by the reciprocal of the probabilities of selection. –The weight for each woman

within a sample PSU is the product of the reciprocals of the probabilities of selecting (1) the

ED or BG, (2) the segment, (3) the DU, and (4)

the eligible sample person. Because of the possibility (sometimes certainty) that certain SMSA’S

and counties could be selected as sample PSU’S

more than once, the first-stage weight is the

reciprocal of the expected relative frequency of

occurrence of the PSU. The first-stage weight is

explained in more detail in the discussion of the

estimating equation.

Nonresponse adjustment. —Each sample

weight is adjusted for nonresponse to the Household Screener (screener nonresponse) and nonresponse of sample women to the detailed NSFG

questionnaire (interview nonresponse). These

adjustments are necessary because the phenomenon of nonresponse introduces bias into any

probability sample. The respondents to a survey

may have a much different distribution of demographic or health characteristics than the nonrespondents. Even if the distribution of demographic and health characteristics is about the

same for respondents and nonrespondents, the

two groups are by definition different because

the respondents participated in the survey while

the nonrespondents did not. Nonresponse

adjustments minimize the impact of nonresponse bias on final estimates by imputing to

nonresponding DU’S and women the characteristics of “similar” respondents. Similar respondents

were judged to be DU’S in the same PSU and

Stratum, and women in the same age-race class

and PSU. Screener response was 89.8 percent for

the entire survey (91.4 percent in Stratum I and

87.6 percent in Stratum II) and ranged from

98.9 percent to 62.5 percent in individual PSU’S.

Interview response was 90.2 percent for the survey (91.2 percent in Stratum I and 88.6 percent

for Stratum II) and ranged from

54.5 percent in individual PSU’S.

100 pe[cent to

Table J. Poststratification adjustment factors (ratio of September 1973 population control totals based on Current

Population Survey data to National Survey of Family

Growth weighted estimates), by race and age

I [

Age I

Negro I

Other

races

14-19 years ......................................... ..........

20-24 years ...................................................

25-29 years ...................................................

30-34 years ...................................................

35-39 years ......................... ..........................

40-44 years ...................................................

0.743

0.927

0.975

0.960

0,876

1.082

1.036

1.088

1.092

0.991

0.951

1.097

Poststratification by age and race.–The

weight for each ever-married respondent is multiplied by a poststratification adjustment factor

that is determined by the woman’s age and race.

The 12 adjustment factors shown in table J

make NSFG estimates of ever-married women in

each age-race class equal to independent control

totals for September of 1973 (the approximate

midpoint of data collection). The control totals

are based on data from the U.S. Bureau of the

Census’ Current Population Survey (CPS). No

poststratification adjustment is applied to the

weights for single mothers because reliable con- ,

trol totals for this population are not available.

Poststratification achieves much of the improvement in precision that would have been attained

if the sample had been drawn from a population

stratified by age and race. The method used to

compute the CPS control totals is discussed in

appendix II as part of the evacuation of alternative estimators.

NCHS decided to use a poststratified estimator instead of a simple inflation estimator

after conducting research to compare the precision of the two estimators. The methodology

and results of the comparison are given in

appendix H.

Estimating Equation

The estimate of an aggregate parameter 1’ is

given by3

Y’=Y; +Y\,

where Y; is the estimate for ever-married

women and Y; is the estimate for single mothers.

14
is a poststratified estimator. The nonresponseadjusted estimates Y’ for the 12 age-race classes

are multiplied by the poststratification adjustment factor X. ~/X~ 1. X; 1 represents the N$$FG

estimate of the numb erAof ever-married women

in age-race class a and Xa 1 is m estimate of the

same population group based upon the CPS.

12

is simply the sum of the nonresponse-adjusted

estimates for single mothers in the 12 age-race

classes.

The nonresponse-adjusted estimator for evermarried women in age-race class a is given by

Yaghzjk “

I

,)

~z, the corresponding estimator for single

mothers, is exactly the same, except that

6aghfk =

w5ghzjk =

the observed value of characteristic

Y for the sample woman selected

from DU k, segment j, ED or BG i,

Stratum h, PSU g, and age-race

class ct.

I

1 if the sample woman whose observed value is Y&h@ has ever

been married;

O otherwise.

the fifth-stage weight applied to the

sample woman represented by

‘agh~k “ The weight is equal to the

number of eligible women in her

DU.

the reciprocal of the original fourthstage sampling rate within segment j.

7.991 if segment j is in Stratum II

and the race of DU k is other than

Negro; otherwise T4g~tik = 1.

the subsampling rate that was applied if segment j was one of the

10 fast-growth segments in Stratum

I; otherwise, F4ghtik = 1.

the subsampling rate that was applied if DU k was associated with

excess missed DU’S; otherwise,

‘4gh~k =

1.

the number of sample DU’S in segment j.

the reciprocal of the probability y

of selecting segment j, the segment

selected from ED or BG i.

the reciprocal of the probability of

selecting ED or BG i from PSU g

and Stratum h.

the number of sample ED’s and

BG’s in PSU g and Stratum h.

an adjustment for screener nonre -

sponse (DU’S for which it was impossible to determine whether or

not there were any eligible respondents). The value Mgh represents the

total number of DU’S from PSU g

.

~d Stratum h, and Mgh is the number of DU’S that were classified as

either including or not including

eligible respondents.

a partial adjustment for person nonresponse, where n.. is the number

of ‘sample person; -in PSU g, agerace class a, and ~ga is the number

of persons who respond. However,

NCHS decided that nonresponse

greater than 50 percent within a

PSU should be adjusted at the class

level rather than the PSU level.

Therefore, when nga is greater than .*

twice nga the nonresponse adjust15
Table K. Examplel of how to determine A& from PSU response

data

Number Number NonreExcess of of re- sponse

PSU number sample spend. adjust- nonrepersons ents in ment spondin class a class a factor ents

ports4~5is used to estimate NSFG variances. An

empirical study by Bean6 gives evidence that the

half-sample technique produces highly reliable,

essentially unbiased variance estimates.

There are three important practical reasons

why hzdf-sample replication is being used:

Totals for

class . ......

1..........................

2 ..........................

3 ..........................

4 ..........................

5 .......................... It43 31

10 10

12 10

13 6

6 5

2 0 t

. . . 3

1 0

1.2 0

2 1

1.2 0

2 2

43 43

1For this example, A- = — ‘—”

43-3 40

ment is defined to be 2, and the excess nonresponse is adjusted in factor Aa described below.

2,000,000/Pg, where P is the 1970

census population of &3U g. This

first-stage weight is the reciprocal

of the expected frequency of occurrence of PSUg in the NSFG sample.

For PSU’S that were completely

contained in a single zone at the

time of selection, WI is the reciprocal of the probabl“flty of selection. However, Wlg deviates from

the reciprocal of the probability of

selection for PSU’S that overlap

zones. For SMSA’S with populations greater than 2 million W1g is

less than 1, whereas the reciprocal

of the probabilityy of selection for

any PSU is always greater than or

equal to 1.

an excess nonresponse adjustment

that compensates at the a-class level

for nonresponse greater than 50

percent in individual PSU’S. Table

K gives an example of how to determine A a,

VARIANCE ESTIMATION

Background

The balanced half-sample

nique described in detail in

16

replication techother NCHS re1.

2.

3.

Programming difficulties are reduced because half-sample variances are computed by taking a simple average of

squared deviations of half-sample estimates from the estimate based on the

full sample. Instead of having to program an exceedingly difficult variance

formula, the programmer must simply

adjust the estimation formula to compute estimates from appropriately chosen

half samples.

The complete algebraic formula for

NSFG variances is unknown because of

the complexity of the design. Although

zdgebraic expressions can be derived for

particular subprocedures–such as the

individual stages of sampling and the

poststratification and nonresponse adjustments–a single, exact variance equation has not been developed.

As stated by McCarthy4 : “Variance

estimates based upon the replicated estimates will mirror the effects of all

aspects of sampling and estimation that

are permitted to vary randomly from

replicate to replicate. ” Also, replicated

half-sample variances include some of the

\’amiabilitydue to nonsampling (measurement) error, as well as sampling variability.

Summary of Applicable Theory

The population of interest is classified into L

strata, and two sample PSU’S are drawn from

each stratum. Selection of exactly two sample

PSU’S reflects an essential element of the theory.

This requirement may be met for noncertainty

PSU’S b~ collapsing t~vo strata having one PSU

each, or for certainty PSU’S by creating two artificial, or pseudo, PSU’S by random methods from

a single PSU. The collapsing method produces

somewhat positively biased (overstated) variance
estimates by introducing a between-stratum

component of variance that does not exist.z

Let the parameter of interest be denoted by

Y, for which an estimate Y’ has been obtained

from the complete sample. Y’ is a linear combination of the sample observations in fully

rigorous developments, although several empirical investigations indicate that the bias of halfsample variance estimates for certain ratio estimators and correlation statistics is negligible,

if detectable at all.ASs>7~s

A half-sample replicate is defined as a collection of L PSU’S obtained by selecting one of

the paired sample PSU’S from each stratum. If

the PSU’S within each stratum are designated by

the subscript i = 1 or 2 and there are K half

samples, where K > L, the pattern may be summarized as in Table L. The “+” indicates that a

PSU falls into a particular half sample, and the

“-” indicates that it does not.

Analogs of Y’ corresponding to each half

sample are then computed. That is, for the kth

half sample, Y’ is given by

h=]

where z’ = either 1 or 2 depending on which PSU

of the stratum is the half-sample k, and ~’i is,

Table L. Exal

Half.

sample

replication

1

2

3

K

Ie of a half-samDie replication oattern

1

Psu —

1

—

+

-1-

—

—

2

—

+

+

—

2

Psu

.

1

—

+

+

—

—

2

—

+

+

—

Stratum

3

Psu —

1

—

+

+

—

—

2

+

+

—

. . .

. . .

. . .

. . .

. . .

.,.

. . .

. . .

—

L

Psu —

1

—

+

—

+

—

—

2

—

+

i-

—

in this example, a total. The estimator Y’ is

L

y’=~(yhl+‘h2)

h=l

and its variance is estimated by

K

Z( 2 .L y; Syt - y’)2

K k=l

Because it is impractical to compute the Yj for

the entire set of 2L possible half samples when L

is large, a subset of half samples is selected to

produce the estimates. A set of side conditions

relating to the selection of PSU’S for the half

samples has been developed by McCarthy4~5

based on work by Plackett and Burmang and

Gurney.10 These side conditions greatly increase

the stability of sy~2 by eliminating a betweenstrata component of variance that is otherwise

present. The value of S$J obtained from a subset of half samples that are chosen according to

the McCarthy criteria is equal to the value that

would be obtained using all 2L half samples. A

set of half samples that satisfy the McCarthy criteria is called a “balanced set,” and the procedure is referred to as “balanced half-sample

replication. ”

Application to the NSFG

In order to apply the balanced half-sample

replication technique, NCHS grouped the 103

NSFG PSU’S into 48 strata. Seven of the strata

were self-representing; that is, the y consisted of

SMSA’S that came into the sample with certainty (except for Boston, which was lumped

with 2 of the 5 New York City PSU’S). Within

each of these strata two pseudo-PSU’s were created by listing the PSU’S in numerical order and

listing the segments in numerical order within

each PSU. The first segment, and every second

segment thereafter was assigned to the first

pseudo-PSU, and the remaining segments were

assigned to the second pseudo-PSU. Within the

other 41 strata, each of the 2 replication PSU’S

consisted of 1 or more NSFG PSU’S (but never

more than one locality). The PSU’S in each stratum belonged to the same geographic region and

17
Figure 2. Relative standard errors for aggregates of women, by race

i=

+’ A’

3 4 56789 A’ 3456789 34 56789 A’ A’

3 456789 3 456789

10 100 1,000 10,000

ESTIMATED NUMBER OF WOMEN (IN THOUSANDS)

Example of use of chart: An aggregate of 2 million women (on the scale at the bottom of the chart) of all races has a relative

standard error of 4.8 percent, or a standard error of 96,000 (4.8 percent of 2 million).
were generally about the same size. The value 1

was assigned to one of the replication PSU’S in

each stratum, and the value 2 was assigned to

the other. Forty-eight half samples were then

formed from the entries in successive columns of

an orthogonal 48 X 48 matrix of 1‘s and 2‘s

adapted from Plackett and Burman.g

In order to estimate the variance of an

NSFG aq regate statistic Y’, 48 half-sample ana-

‘9 logs of 1’ were computed. The formula for the

Ath half-sample estimate is

where

and

~=1

Y~lk and X~l ~ were computed in exactly the

same way as Y~l and -Y: 1. No additional

weighting was necessary because of the poststratification process. On the other hand, the Y~2k

were computed after multiplying the weight for

each sirrale mother bv 2 to com~ensate for the

half-sam~le procedur;. The

then estimated by

.

variance of Y~ was

- y32

Types of aggregate statistics produced from the

NSFG include number of currently married

women, number of ever-married women, number of pregnancies for ever-married women, and

total number of children born to ever-married

women. Half-sample variances were not computed for all aggregate statistics because the time

and money needed to do so would have been

prohibitive. In addition, data reports would be

much more cumbersome if a variance estimate

were published for each statistic. To avoid these

problems, variances for each type of statistic

were computed only for selected population

subgroups, which were chosen to represent a

wide variety of demographic characteristics and

a wide variation in the size of the estimates.

Curves were fitted to relative standard error

(RSE) estimates for number of currently married women and number of pregnancies, according to the model

‘SE(Y’)=E=J

A and B are parameters whose estimates determine the shape of the curve. The rationale for

the model and the iterative method that was

used to estimate A and B are explained elsewhere.’ I

Figure 2 shows relative standard error curties

for estimates of women by race. The estimates

of A and B for the curves are shown in table M.

Although the curves for women were fitted to

RSE’s for estimates of currently married worn%

only, RSE’S for estimates of ever-married women

fail close to the curves. Therefore, it is appropriate to obtain predicted RSE’S for estimates of

ever-married women from the aggregate curves

for women.

Separate curves were needed for Negro

women and women of all other race classifications (women of all races, women of race other

than Negro, and white women). Because Negro

women were oversampled, an estimate of a given

number of Negro women has a smaller RSE than

an estimate of the same number of women of all

races. The curves in figure 2 clearly show this

relationship. For example, an estimate of

200,000 Negro women has an RSE of 9 percent,

while an estimate of 200,000 women of all

races has an RSE of 15 percent.

Table M. Estimates of A and B for relative standard error curves,

by race

Curve A I B

Total and white women ....... .......

I

0.000017613 4,493.7916

Negro women .............................. 0.000040219 1,600.4393

t I

19
Variances of aggregate statistics were used to

derive variances of percents, which are ratios of

two aggregates with the numerator being a subclass of the denominator. Percent estimates

usually show the proportion of a population

that has a particular characteristic of interest.

The RSE of the percent estimate

p’ =;:. 100”

is given by the expression 1

RSE (P’)= ~ [RSEZ (Y’) - RSEZ (Z’)]

an acceptable estimate for the RSE of a percent whose denominator is not one of the values

shown in figure 3.

In addition to percents, the NSFG provides

other types of ratio estimates where the numerator is not a subclass of the denominator, such as

the mean number of expected births per woman,

the mean number of expected additional births

per woman, and the probability that a woman

gives birth within a certain number of months

following her last previous birth. Variances for

these types of estimates could not be derived

from variances of aggregate statistics, so they

were computed directly by the half-sample technique. The variance of the ratio estimate R‘ =

Y’/W’is given by

1

. J/l+;- (A+;)

1

‘E

J

BZ’- BY’(P’/Y’)

=

Y’Z’(P’/Y’)

J

B(lOO -P’)

=

P’z’

where B is the least squares estimate from the

error curve for Y’ and Z’.

The RSE of P’is dependent upon the values

of both P’and Z’. In order to account for the

variation in error due to P’and Z’, a set of percent RSE curves was derived from each aggregate

RSE curve. Each curve in the set yields RSE’S

for percent estimates with a fixed denominator.

Figure 3 shows the set of curves for percent

of total and white women, along with an example of how to use the error chart. Each curve

satisfies the equation

RsE@)=~

where P’is the estimated percent and Z’ is the

denominator of P’.Linear interpolation yields

where R: is the kth half-sample analog of R‘.

As was the case for aggregate statistics,

approximate error curves were fitted to selected

variance estimates. The model for these more

complicated ratio estimates was

RSE (R’)=

Jw

‘JzF7’

where A, B, and C were the parameters to be

estimated. As with percentage estimates, the

RSE varies with the size of the estimate R‘ and

its denominator W’. The method of estimating

A, B, and C is the same general method used for

aggregate estimates.l 1 The RSE’S for each type

of ratio statistic are represented by a set of

curves, as was the case for percent estimates.

Figure 4 shows the set of curves for mean

number of births expected by women of all

races, along with an example of ho~v to use the

error chart. The three cur;es in

the equation

the chart satisfy

RSE(R’) = #0.00002488 - 649.05239 /R’W’ + 1,733.8522/W’

20
Figure 3. Relativa standard errors for percent of total and white women (base of percent shown in curve in thousands)

100

90

80

70

60

I

I I I r 1 f IITI lJ50 ---

, , , I , , , , , , I Ill [ 1 1 1 1 r I ! 1 1 1 1 1 1 1

ml I I II

1 I I 1111 Ill [ 1 I I I I 1111111 40 200 I

dllllttmm I I I I I Illllltttttt 30

20

10

9

8

7

6

5

Llll 1111111111111

I I I I I 1 I I 1 I I

I 1 I 1 I I I I I I Ill

4

, 1 1 t n 1 1 I 1 1 1 1

I I I I I I 1!/!! 1 1 , , r , r r 1 r

3

2

1

.9

.8

.7

.6

.5

I I ! I I 1 I I I I 1

.4

.3

.2

.1

A

2 3 456789

A

2 3 456789

i

2 3 456789

A

1 10 100 1,000

ESTIMATED PERCENT

Example of use ofchzrt: An estimate of 10 percent (from the scale at the bottom of the chart) of

a population subgroup of 1 million women (fifth curve from the top) has a relative standard error of

20.0 percent, or a standard error of 2.0 percent (2o.o

where R’ is the estimated mean and W’ is the

estimated number of women (the denominator

of R’). Linear interpolation yields an acceptable

estimate for the RSE of R‘ when R‘ is not one

of the \’alues shown in figure 4.

Figures 2-4 are examples of relative standard

percent of 10 percent).

error curves for the various kinds of statistics

produced from Cycle I of the NSFG. Each report that discusses findings from Cycle I will include similar charts for all types of statistics

presented therein.

An estimate of the standard error of the dif21
Figure 4. Relative standerd errors for mean numbers of Mrths expectedby women of all races and white women

IJJ

>

1 10 100 1,000 10,000

ESTIMATED NUMBER OF WOMEN IN THE DENOMINATOR (IN THOUSANDS)

Example of use of chart: An estimate of 2.0 births per woman (middle line on the chart) for a r)o~ulation submouD of

900,000 women (read- from the scale at the bottom of the “chart) has a ;elative standard error of ~.O per;e~t, or a stand~rd &ror

of 0.08 (4.0 percent of 2.0).
ference between any two aggregates, percents, or

other ratio statistics is given by

This expression provides a good estimate of the

standard error for uncorrelated statistics, but

can only be considered a rough approximation

otherwise. Because NSFG estimates are based

upon a large sample of women, the distributions

of Yj and Yj (and, therefore, Y: - y:) are

approximately normal. Frankell z shows empirically that, using balanced half-sample replication

estimates of variance, the test statistic

Y; - Y;

‘=s (Y1- Y2)

approximates the student’s t distribution under

the null hypothesis of no difference between

the parameters estimated by Y; and Yj against

a two-sided alternative. The number of strata in

the replication design (48 for the NSFG) can

reasonably be used as the number of degrees of

freedom for the t statistic, although the exact

value for the degrees of freedom is unknown.

Therefore, individual two-tailed significance

tests of differences between NSFG statistics can

be performed with an approximate significance

level of a by computing t and comparing it to

the two-tailed 1- & critical value for the t distribution with 48 degrees of freedom.

Example: Suppose 500,000 currently

married Negro women expect an average of

2.46 births per woman and 5 million currently married women of other races expect

an average of 2.08 births per woman. To

test this race difference at the Q’ = .05 level

of significance, compute

t= 2.46-2.08

-~ (2.46 )2RSE2 (2.46)+ (2.08 )2RSE2 (2.08)

From figure 4, RSE(2.46) * .055 and

RSE(2.08) ~ .018 so that

2.46-2.08

t=

~(2.46)2 (0.55)2 + (2.08)2 (.018)2

= 2.71

The two-tailed .95 critical value (1 - u) for .

a t statistic with 48 degrees of freedom is

2.01. Therefore, the difference is significant

at the .05 level.

o 00

23
REFERENCES

1King, B. F., and Frankel, M. R.: Description of the

Sample Design for the National Family Growth Survey.

Unpublished manuscript. ,

2Kish, L.: Survey Sampling. New York. John Wiley

& Sons, 1965. ,

3Brock, D. B.: Estimation and Variance Specifications for the National Sui-vey of Family Growth. Unpublished manuscript.

4National Center for Health Statistics: Replication:

An approach to the analysis of data from complex surveys. Vital and Health Statistics. PHS Pub. No. 1000-

Series 2-No. 14. Public Health Service. Washington.

U.S. Government Printing Office, Apr. 1966.

5National Center for Health Statistics: Pseudoreplication: Further evaluation and application of the balanced half-sample technique. Vital and Health Statistics.

PHS Pub. No. 1000-Series 2-No. 31. Public Health Service. Washington. U.S. Government Printing Office, Jan.

1969.

6National Center for Health Statistics: Distribution

and properties of variance estimators for complex multistage probability samples: An empirical distribution.

Vital and Health Statistics. Series 2-No. 65. DHEW

Pub. No. (HRA) 75-1339. Health Resources Administration. Washington. U.S. Government Printing

Office, Mar. 1975.

7Simmons, W. R., and Baird, J.: Use of pseudoreplication in the NCHS Health Examination Survey. Proceedings of the Social Statistics Section of ASA. American Statistical Association, 1968.

8Kish, L., and Frankel, M. R.: Balanced repeated

replications. ]. Am. Stat. Assoc. 65:1071-1094, Sept.

1970.

‘Plackett, R. L., and Burman, J. P.: The design of

optimum multifactorial experiments. Biometrika 33:

305-325, 1946.

1‘Gurney, M.: The Variance of the Replication

Method for Estimating Variances for the CPS Sample

Design. Dittoed memorandum, U.S. Bureau of the

Census, 1962.

11 National Center for Health Statistics: Estimation

and sampling variance in the Health Interview Survey.

Vital and Health Statistics. PHS Pub. No. 1000-Series 2,

No. 38. Public Health Service. Washington. U.S. Government Printing Office, June 1970.

‘ 2Frankel, M. R.: Inference from Survey Samples:

An Empirical Investigation. Ann Arbor. Institute for

Social Research, University of Michigan, 1971.

‘ 3 French, D. K., and Bryant, E. E.: SamplcDependent Estimation for the National Survey of

Family Growth. Proceedings of the Social Statistics

Section of ASA. American Statistical Association, 1976,

24
APPENDIXES

CONTENTS

I. Glossary of Terms .......................................................................................................................... 26

II. Evaluation of Mternative Estimators .............................................................................................. 28

111, Household Smeener ........................................................................................................................ 29

25
APPENDIX

GLOSSARY OF

Conterminous United States. –The land area

consisting of the District of Columbia and all

States except Alaska and Hawaii.

Dwelling unit (D U).–A single room, or

group of rooms, that is intended for separate living quarters. The people who live there must

live and eat separately from everyone else in the

building (or apartment ) and the room or group

of rooms must have either

1.

2.

A separate entrance directly from the

out side of the building or through a

common hall, or

Comdete kitchen facilities for the use

of t~is household only. Complete kitchen facilities include all of the following:

a. a range or cooking stove, and

b. a sink with piped water, and

c. a mechanical refrigerator,

Education. –The highest grade of school

completed.

Geographic region.–For the purpose of classif ying the population by geographic area, the

U.S. Bureau of the Census has grouped the 50

States and the District of Columbia into four

regions, as follows:

Region States included

Northeast ......... Maine, New Hampshire, Vermont, Massachusetts, Rhode

Island, Connecticut, New

York, New Jersey, Pennsylvania

1

TERMS

North Central...

South ...............

West .................

Michigan, Ohio, Indiana, Illinois, Wisconsin, Minnesota,

Iowa, Missouri, North Dakota, South Dakota, Kansas,

Nebraska

Delaware, Maryland, District

of Columbia, Virginia, West

Virginia, North Carolina,

South CaroIina, Georgia,

Florida, Kentucky, Texas,

Tennessee, Alabama, Mississippi, Arkansas, Louisiana,

Oklahoma

Montana, Idaho, Wyoming,

Colorado, New Mexico, Arizona, Utah, Nevada, Washington, Alaska, Oregon, California, Hawaii

Alaska and Hawaii are not included in the NSFG

sample design.

Household. –A family living together, or five

or fewer unrelated individuals living together in

a DU.

Parity. –The number of live births a woman

has had.

Screener interview. –A preliminary interview

at the household to collect information about

the DU and to determine whether or not the

househoId includes one or more women who are

eligible for the detailed interview.

Standard metropolitan statistical area

(S.MSA).–A county or group of contiguous

counties (except in New England) which contains at least one central city of 50,000 people

or more, or “twin cities” with a combined popu26
~

Iation of at least 50,000. In addition, other con- of the Census, the urban areas of the United

tiguous counties are included in an SMSA if, States include all cities or “twin cities” with at

according to certain criteria, they are socially least 50,000 population in 1970 together with

and economically integrated with the central the surrounding closely settled area and all

city. other incorporated or unincorporated populaUrban area.–As defined by the U.S. Bureau tion centers with 2,500 inhabitants or more.

000

27
APPENDIX II

EVALUATION OF ALTERNATIVE ESTIMATORS

An aggregate parameter Y for all eligible

women less than 45 years of age in the United

States can be written as Y = YI + Yz, where YI

is the total for all ever-married women and Y2 is

the total for all single mothers with one or more

of their children currently living in the household. A1temative estimators of Y considered for

the NSFG were

Y’~p=Y; +Y; (1)

and

Y;= Y:+Y; (2)

where Y; and Y! are simple inflation estimatw-s

and

is a poststratified estimator. The X&l represent

NSFG estimates of the number of ever-married

~omen in each of 12 age-race classes and the

Xal are corresponding estimates for September

1973 (the approximate midpoint of NSFG interviewing) based upon the U.S. Bureau of the Census’ Current Population Survey (CPS).

At the time the two estimators were proposed, it was decided that the choice of Y: or

Y~P as the official estimator for the NSFG

would be based on information from the sample

data. Values of certain statistics would be calculated using both estimators, and variances of

the two competing estimates would be computed using identical half-sample replication procedures. If the variance of Y: was the lower of

the two variances for many of the experimental

statistics, and if Y$ did not result in higher variances for more than a few statistics, then it

would be chosen; otherwise, YjP would be used.

Simple inflation and poststratified estimates of the number of currently married U.S.

women and the relative standard errors (RSE’S)

of both estimates were computed for more than

200 subdomains of the population. The poststratified estimator had a smaller RSE than the

inflation estimator for more than 80 percent of

the domains. The improvement in precision was

20 percent or better for almost two-fifths of the

domains. A more complete discussion of the

design and results of the study can be found

elsewhere. 13

Because the RSE of Y; was much smaller

than the RSE of YjP for many aggregate estimates, and was no more than 10 percent larger

than the RSE of YjP for any parameter in the

study, the decision was made to use Y$ as the

official NSFG estimator.

NOTE: The list of references follows the text.

000

28
APPENDIX Ill

HOUSEHOLD SCREENER

NORC-4604

July, 1973

BEGIN DECK 21

r

NOTICE:

OFFICE USE ONLY

Final Status❑ 10

Tel. Re-Check:

I

Yes. .o. l

No . ...2

11

ONB No. 68 - S72170

NATIONALOPINION RESEARCHCENTER Expires:April 30, 1974

Universityof Chicago

Collectedfor the National

Center for Health Statistics

HOUSSHOLDSCREENER

All informationwhich would permit identificationof any

individualwill be held in strict confidence,will be used

only by personsengagedin and for the purposeof the survey, and will not be disclosedor releasedto others for

any purpose,as in accordancewith Section305(a)of the

Public Health ServiceAct, Section1.103(a)of the Public

Health ServiceRegulations[42 CFR 1.103(a)]and under

Public HealthDelegationof AuthorityNmber 31.

ASSIGNMENTBOX

r

SAMPLINGTABLE

IF NUMBER OF THEN lNTERVIW

1

ELIGIBLE FENALES PERSON LISTED

LISTED IN SUM- ON SUMMARY EOX

WRY BOX 1S: LINE

El Two

Three

Four

Five

L -J 1=’1 I

INTERVLBWBR: Is this addressin a rural%rea or in some other kind of area?

Rural . . . 1 Other . . . 2 12

INTRODUCTION

Hello, I’m from the NationalOpinionResearch Center.

(SHOWID BADGE.) A letterwas sent to you recentlyexplainingthe

studywe are conductingfor the U.S. Public Health Service. As yOU

may recall from the letter,the study is being conductedall over

the countryand is about familysize.

RECORD OF ALL CONTACTSAT HOUSEHOLD

${k Date ‘lime ‘p’

CODE ONE Interv’r

PerjTel Results Ser. uex initials

.
-2- TIME AM

BEGAN: PM

rnOusEnOLDENUME8AT10N

n ,0,,

BEGIN DECK 22

1, TO start, how many people live in this household? NumER

2, What is the name of the heed of this household? (ENTER NANE ON LINE 01 BELOW. )

3. And the other members of this ho.sehold--uh.w are their name.? Let8s begin with

everyone related to (HEAD). BE su~ PERSON 1t:cL0TIE5 (HlM5ELFl Herself).

NAIEs IN TABLE BELOW.)

(ENTER

4. Are there other people living here who are not related to (HEAD)?

5. I have listed (READ mm IN ORUER). Is there anyone else staying her. n.w, such

ss friends, ,,lat i”,, or roomers?

AFTSRLISTING HOUSEHOLD,

ASK QS. 6-9 FOR EACH PERSON

AS APPROPRIATE A

what CODE

(PE:OX) , S

SEX

(ASK relation- ~F

ship to

(HEALJOF y;

ROUSEsom) 7

Vxous)

6. 7. 8. 9. IF 13 YEARS OR OWES ASK: 1S

flow old (PER30X) no. ci.rried,widowed,di.

vorcedor annulled,separatedor has

(he/she) neverbee.mrried? IF NEvER >NRRIED m RE?ORTELIAS LmxG

TOGETHER, CODE ‘TXFO!L.L4L.,$ IF WVER

mRRItD ASD KOT LIVC+G TOG2THER BUT

HAS m’N cHzLDR3N, CUDE I,WITH OLT

CHILDREK.,,

ln- Si”gld

~rr for-wid.

Div. Sep. with Never

FirstName LastName M F

km. rated .;?. slam. . .,1 d,,”

12 Is

01 HEAD

14 15 16

12 12 3456 7

17 1s

02

19 2U 21

12 12 3456 7

22 23 24 is

03

26

12 12 3&56 7

27 28 29 3U

04

31

12 12 3456 7

S2 S3 3U S5

05

36

12 12

9

3456 7

37 38

06

39 40 41

12 12 3456 7

,2 43

07

4k 115 46

12 12 3456 7

47 6s

08

., 50 51

12 12 3456 7

52 3,

09

5, 5s 56

12 12 3456 7

57 Sn

10 ‘

59 60 61

12 12 3456 7

IF MOHE THAN 10 PEOPLE IN HOUSEHOLD, GO T@ CON2’INIM’fION BOOKLET,PAGE 2.

.,s

(HESW

PERSOX)

(hi$her)

last

birchday7

10. 1, there anyone no..way from h.rm who usually 1iv.. her,?

❑ Ye. n . .

11. Do .,,3’ Qf the PC,P1, i,,this I,,usc!, cld ha,., , 1,.-. ,,:yxh.,, ,,,,:

12, Are my of the persons m th~s l:o. seh..ld now m full-time acti\.e duty with the

Anneal Force, of the L’nicedSt.:e,-

❑ Yes D NO

. ...

I

~

30
-3-

13. SELECTION OF RSSFONDENT

(cHECK ONE BOX)

DECK 21 CON’TINUEO

10

2EI

3CI

❑

NO ELIGIBLE 140MEN UI$DER 65 YRS. OF AGS,

NO INTERVISW REQUIRSD; SKIP TO Q. 14.

ONE SLIGISLE VONAN UNDER 45 YRS. OF AGE,

CURRENTLY ~ OR INFORMALLY MARRIED;

CIRCLE R* S PERSON NUI!BER ON P. 2 ;

SKIP TO Q, 14; THEN USE lcusRENTLY NARRIED wEETloNNAIR~

ONE ELIGIBLE !40NAN UNDER 45 YRS. OF AGE,

CURRENTLY _, SEPARATED, _ OR ANNULLEO, OR SINGLE W/OrNNCHILDREN;

CIRCLE R’ S PERSONN07LBERON P. 2:

SKIP TO Q. 14; TH2N USE[P05T-NkRRIEo OUESTIONNAIRE~

NOSE THAN ONE ELIGIBLE wOitiN WDER 45 YRS. OF AGE,

FDLLOWSTEPS 1 - 4 ‘2U SELECT CORRECT RESPONDENT

S!SIG: List names of elisible w

females in Summary Box

--in order of ase, begfnning with the oldest

.“ Ll”e #1. M

II SUMMARY BOX

14 11.!

Line # Nam Age

I

Ha

1

2

3

4

5

6

5

US. Sanpling Table on pase 1

to determine which eligible

female to interview.

Circle R’s L%ne # in Summary

Box, and write selected R’s

name here:

(Respondent’s Nune)

(cHECK ONE BOX)

•1

•1

—

14. ASK EVERYOSE: Flay 1 have your telephone “.mber (in case my office wants to verify this interview)?

Telephone n.. : Area Code: I 17

No.hone . . . . . . . . . . . . ...2

IF P1lD1lE SO. GIVEN. CODE LOCATION “

_

Se fad, . . . . . . . . . . . . ...3

lnllouseholJ . . . . . . . . . . ...4

I.hmnof neighbor . . . . . . . ...5

<— Other (SPECIFY) . . . . . . . . . ...6

TINE SCREENER AM

Thank you very much for your help. Eh3ED : PM

INTERVIEWER: FILL OUT A-F BELOW k SANPLING REPORT & INTERVIEWER SIGNATURE AND NUhBER ON

PAGE 4 IMMEDIATELY AFTER YOU LEAVE THE HOUSEHOLD.

A.

s.

Race of household (by ob,erv.ation)

Slackltlegr o ...,..... .,1

white . . . . . . . . . . . . . ..2

Other (SPECIFT)

3

Nocable to observe..,.. . ..4

Code t,w of living quarters:

Dctacbed single family house . . . . . . 1

Trailer . . . . . . . . . . . . . . . ...2

2-4 fcanily houselapartment buildins . . . . 3

Row house (3 . . mare attached unit. ) , . k

Apartment house (5 or more unite.; free

access to housins units) . . . , . . . . 3

Aparttoe”t house (5 or more units; locked

entry, or g.ardod by doorman, or both) . 6

Other (SPECIFY)

7

c. LenStb of time

1s for Screener:

min”tea

D. ‘“” ‘f “’’’””: Q m

E. With whom did you ccmduct the Screener?

19 [same (,) of screener i. fomant (s)]

20 21

22 2s

28 27

F. If screener informant ~ household member,

describe relationship to selected re*P.ande”t . . co household.

(Relationship to Household)

[GO TO PAGE L I

31
G.Y

M

*

c

*

CHECK (~ HERE IF NO

MISSED DU OR OTHER I

ICORRECTIONS

7]

%

AT SAMPLEADDRESSL

OFFICEUSE ONLY

DU Line

Code

(10 (11!17

?hone

call

Col.

1

2

3

4

5

6

7

8

Psu

Address

Corrections,Additions,

or

Deletions

—

SANPLING

Description

%. #_

REPORT

of

ON MISSED

Part

DUiS AND OTHER CORRECTIONS m

Corrections,Additions,

or

Deletions

.

Total AdditionalI)ULs

sample Line # Case # 1 u

DU’s Added DU’S Deleted OFFICEUSE CorrectionAddltIons AddLtlons ddztzons

to at Same at Same between Line ONLY

Line #

Reason BLOCK#

(f%%?) (Ci%~kij)‘Na%ip ‘} (77-80)

I

I

1

I

I

I

I

I

,

I

I

+-

,

I

I

I

I

I

,

I

I

1

I I II

M I I

!

IF 1 TO 4 DUIS:

DECK 21

FILL OUT HOUSEHOLDSCRSENSRFOR EACH & CONDUCTSCKEENRRIN2ERVIEW.

=T

IF 5 OR MORSDU’S:

CALL SANFLINGDE~. (cOLLECTAC 312/684-56oo)FOR INSTRUCTIONS

_ YOU DO ANT ADDITIONALSCKSENERINTERVIEWS.

INTERVIEWER I I I I

20 32

ID NUMBER:

AT TIIE OF PHONE CALL, CIRCLE CODE IN “PHONECALL COL1lFOR LINE(S)

AT WHICH YOUARI INSTRUCTED’20IXlSCREENERINTERVIEW(S);

THEN FILL OUT SCREENERFOR EACH OF THOSE & CCJ:DU.:r

SC8.EEN8RINTERvIEw.
VITAL AND HEALTH STATISTICS PUBLICATIONS SERIES 

Foremerly Public Health Service Publication No. 1000 

Series 1. Programs and Collection Procedures. -Reports which describe the general programs of the National 

Center for Health Statistics and its offices and divisions, data collection methods used, definitions, and 

other material necessary for understanding the data. 

Series 2. Data Evaluation and Methods Research . -Studies of new statistical methodology including experimental 

tests of new survey methods, studies of vital statistics collection methods, new analytical techniques, 

objective evaluations of reliability of collected data, contributions to statistical theory. 

Series 3. AnaZy tical Studies. -Reports presenting analytical or interpretive studies based on vital and health 

statistics, carrying the analysis further th .an the expository types of reports in the other series. 

Series 4. Documents and Committee Reports. -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 10. Data from the Health Interview Survey. -Statistics on illness; accidental injuries; disability; use of 

hospital, medical, dental, and other services; and other health-related topics, based on data collected in 

a continuing national household interview survey. 

Series ll*, Data from the Health Examination Survey. -Data from direct examination, testing, and measurement 

of national samples of the civilian, noninstitutionalized population provide the basis for two types of 

reports: (I) estimates of the medically defined prevalence of specific diseases in the United States and 

the distributions of the population with respect to physical, physiological, and psychological characteristics; and (2) analysis of relationships among the various measurements without reference to an 

explicit finite universe of persons. 

Series 12. Data from the Institutionalized Population Surveys. -Discontinued effective 1975. Future reports from 

these surveys will be in Series 13. 

Series 13. Data on Health Resources Utilization. ,-Statistics on the utilization of health manpower 

providing long-term care, ambulatory care, hospital care, and family planning services. 

and facilities 

Series 14. Data on Health Resources: Manpower and Facilities. -Statistics on the numbers, geographic distribution, and characteristics of health resources including physicians, dentists, nurses, other health occupations, hospitals, nursing homes, and outpatient facilities. 

Series 20. Data on Mortality. -Various statistics on mortality other than as included in regular annual or monthly 

reports. Special analyses by cause of death, age, and other demographic variables; geographic and time 

series analyses; and statistics on characteristics of deaths not available from the vital records, based on 

sample surveys of those records. 

Series 21, Data on Natality, Marriage, and Divorce. -Various statistics on natality, marriage, and divorce other 

than as included in regular annual or monthly reports. Special analyses by demographic variables; 

geographic and time series analyses; studies of fertility; and statistics on characteristics *of births not 

available from the vital records, based on sample surveys of those records. 

Series 22. Data j?om the National Mortality and Natality Surveys. -Discontinued .effective 1975. Future reports 

from these sample surveys based on vital records will be included in Series 20 and 21, respectively. 

Series 23. Data from the National Survey of Family Growth. -Statistics on fertility, family formation and dissolution, family planning, and related maternal and infant health topics derived from a biennial survey of 

a nationwide probability sample of ever-married women 1544 years of age. 

For a list of titles of reports published in these series, write to: Scientific and Technical Information Branch 

National Center for Health Statistics 

Public Health Service 

Hyattsville, Md. 20782