FROM VITAL & HEALTH STATISTICS OF THE NATIONAL CENTER FOR HEALTH STATISTICS 

LE. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE I No. 10 August 12, 1977 I Public Health Service. Health Resources Administration 

Expected Size of Completed Family Among Currently Married 

Women 15-44 Years of Age: United States, 1973a 

Currently married women aged 40-44, who 

are near the end of their childbearing period, 

expect to have an average of 3.3 children. But 

those aged 20-24, who are beginning their childbearing, expect an average of only 2.3 children. 

Although the younger women are less sure about 

their expectations than the older women, the 

statistics reflect definite age differences in birth 

expectations. If realized i; actmd fertility, Fige 1 shows that these differences wiIl result in a 

ignificant decline in completed family size. 

m The expected decline in fertility is found in 

Figure 1. Average number of children ever born and total 

births expected per currently married woman 15-44 ywn 

old by age: United States, 1973 

15-44 15-19 20-24 2s-29 30-34 35-3S w 

AGE IN YEARS 

� ‘Prepared by Gordon Scott Bonham, Ph. D., DivKlon 

of Vital Statistics. 

nearly all subgroups of the population, even 

though there are different levek of expectations 

among these subgroups. For instance, the total 

number of births expected by currently married 

women decreases as education increases and as 

age at marriage increases. Also, Negro wives, 

Catholic wives, wives who participate more in 

religious activities, wives who are not in the 1abor force, and wives whose first chiId was born 

before marriage, expect more total births than 

other wives. 

These and other findings presented in this 

report are from Cycle I of the National Survey 

of Family Growth (NSFG), conducted by the 

National Center for Health Statistics. The NSFG 

was designed to provide information about 

fertility, fa.ndy pkmning, and aspects of maternal and chiId health reIated to childbearing. 

Data on these topics were collected by personal 

interviews with about 9,800 women aged 15-44 

years who had ever been married or who had 

children of their own living in the household. 

Interviews were conducted between July 1973 

and February 1974, centering on September 

1973. The statistics in this report refer to currentIy married women Iiving in the conterminous United States, and are based on interviews with a representative sample of 7,566 such 

women. Further discussion of the survey design, 

definition of terms, and sampIing variability are 

in the TechnicaI Notes. 

RANGE OF BIRTH EXPECTATIONS 

The number of births that women expect to 

have may not forecast future births accurately 

because women may change their minds, they 
2


may not be able to have the expected births, or 

they may unintentionally have more births than 

expected. The NSFG allowed for some of these 

uncertainties in interviewing women on expectations. Wives were asked how many additional 

births they intended to have, if any, and how 

certain they were of achieving those intentions. 

Those who expressed uncertainty, about onethird of the total, were asked the minimum and 

maximum numbers they actually expected to 

have. 

The range of births expected per 1,000 currently married women 15-44 years old is shown 

in table 1. Overall, women expected to have 

between 2,653 and 2,985 births per ,1,000 

women (or 2.7 and 3.0 births each) by the time 

they finish childbearing. Of these expected 

births, 2,180 (or 2.2 births each) have already 

occurred. The difference between minimum and 

maximum expected births decreases as age increases. Most of this difference is due to the 

higher proportion of expected births that have 

already occurred among older women and therefore present no uncertainty. About one-fourth 

of the minimum births expected by women 

15-19 years old have occurred, and this proportion increases to almost 1.00 percent for 

women 40-44 years old. 

Regardless of the certainty of her intentions, 

a central number of births was determined for 

each woman by a procedure described in the 

Technical Appendix. The central number of 

births expected by women in the sample population is between the minimum and maximum, 

although it is slightly closer to the minimum. 

This number increases with age, except for a statistically insignificant decrease between ages 

15-19 and 20-24. The increase is not solely due 

to events associated with different stages of the 

life cycle. It also represents diversified birth expectations of different cohorts of women. Those 

aged 40-44 in 1973 had most of their children 

during the high fertility period of the 1950’s and 

the early 1960’s, often referred to as the “baby 

boom.” However, women in their twenties in 

1973 were starting their families during a period 

of low fertility. The age compariso~ in table 1 

reflects the changes in fertility shown in table 

A. There is not much difference in the number 

of total births expected or children ever born by 

the time of the interview among women aged 30 

or over between 1960 and 1973. However, there 

are dramatic changes for women under age 30. 

Wives 18-24 years oId in 1973 expect to have an 

average of 0.8 chiIdren fewer by the time they 

complete childbearing than wives 18-24 years 

old in 1960 or 1965. Wives 25-29 years old in 

1973 expect to have 1.0 fewer children than 

wives of a similar age in either 1960 or 1965. 

This expectation of sm~er families is not unreasonable since they have already had an average of 0.5-0.8 fewer children than the wives of 

comparable age 8 to 13 years earlier. 

COMPARISON WITH 

OTHER DATA 

Other surveys have collected data on birth 

expectations, as indicated in table A. Most 

notably, the U.S. Bureau of the Census asked 

about birth expectations in the June 1973 Current Population Survey (CPS). A comparison of 

the NSFG of 1973 with the CPS of 1973 

shown in table B. Except for wives 35-39 year m old, the NS FG reports sIightly higher birth expectations than the CPS does. While the differences are of demographic significance, they 

are approximately equal to the standard error of 

the differences, and thus not statistically significant. The small differences in the two estimates could be due to differences between the 

surveys in any or all of the following: 1) allowances for uncertainty in birth expectations in 

the NSFG, 2) characteristics of wives reporting, 

3) dates of survey, 4) total content of the 

interview, or 5) categorization of marital status. 

BIRTHS DESIRED 

The number of births that a woman would 

like (or desire) if she could have just the number 

she wanted, is shown in table 1. The number of 

births desired by wives of all ages is approximately equal to the centraI number of births 

they expect to have. However, wives under age 

30 expect to have fewer births than they would 

like, while wives age 30 or older expect to have 

more births than they would like. These dif, 

ferences could be due to chfferential ability too 

control fertility, specific temporal conditions or 

i 
admcdaa3 

Table A. Average number of total births expected and children ever born per currently married woman 18-39 years old in selected years 

by age: United States, 1960-1973 __ - . 

Total births expacted, children 

ever born and age 

196P 1965a 1967b 1970a 1971 b I 1972b 1973C I 

Total births expected 

18-24 years old . ... ... ... .. ..... .. . .. 3.1 3.1 2.9 2.6 2.4 2.3 2.3 

25-29 years old ... .. ... .. .. ..... .. ... 3.4 3.4 3.0 2.8 2.6 2.5 2.4 

30-34 years old .. ... ..... . .. .... .. . .. 3.3 3.6 3.3 3.1 3.0 2.9 2.9 

35-39 years old .... . ..... .. . .... . .. .. 3.0 3.4 3.3 3.4 3.3 3.2 3.2 

I I 

Children ever born 

18-24 years old ....... ............... 1.4 1.5 1.2 1.1 1.0 0.9 0.9 

25-29 years old ...................... 2.4 2.5 2.3 2.1 1.9 1.8 1.7 

30-34 years old ...................... 2.7 3.1 3.1 2.9 2.8 2.7 2.6 

35-39 years old ...................... 2.7 3.2 3.2 3.3 3.2 3.2 3.1 

aFigures are from the 1960 Growth of American FamWles Survey and the 1965 and 1970 National Fertility Surveys as reuorted in 

U.S. Bureau of the Census, Current Population Reports, Series P-20, No. 263 (April 1974), table C. 

bU.S. Bureau of the Census, Current Population ReDOtiS. Series P-20. No. 269 (Seutember 1974). -. . . ‘National Survey of Family”Growth. -

Table B. Number of total births expected per 1,000 currently having borne 20 percent of their expected births, 

married women 18-39 vears of aae for the National Survev of while wives age 40-44 have borne 99 percent of 

Family Growth and the Curren; Population Survey: Unked � States, 1973 their expected births. Wives 15-19 years old expect to have 79 percent of their births by the time 

National they are 20-24, whiIe wives 20-24 years oId at the 

Current 

Survey of Population date of the survey had only had 40 percent of 

Age	 Family Survey their expected births by this same age. Similarly, Growth 

wives 20-24 years old expected to have 85 per18-39 years ............... 2,674 2,639 cent of their total births by the time they are 

25-29 while wives currentIy 25-29 years old have 

18-24 years ... .................. 2,320 2,262


25-29 years ..................... 2,445 2,387 had 68 percent of their births. These obser-


30-34 years ..................... 2,879 2,804 vations suggest at least one of the following: 1)


35-39 years ..................... 3,183 3,234 women who many at younger ages, who pre-


Source: Data for the Current Population Survey is from U.S. dominate among women aged 15-19, have difBureau of the Census, Current PopuLrtfon Reports, Series P-20, ferent patterns of childbearing than women who NO. 265, “FertiMy Expectations of American Women: June 

marry at slightly older ages, who are more nu- 1973,” Washm.gton. U.S. Government Printing Office, 1974. 

merous among women aged 20-24; 2) births 

among younger women are concentrated within 

differential interpretations of expected and a na-ro wer time period than they were among 

desired numbers of births. There is less variation older women; or 3) younger women do not have 

by age of women in the number of births they realistic expectations of the timing of their fudesire than in the number of births they actually ture births. 

expect. 

VARIATIONS IN BIRTH EXPECTATIONS 

TIMING OF BIRTHS 

Table 1 shows that Negro wives at alI ages 

e Table 2 shows that 78 percent of the total expect to have more total births than do white 

irths expected by currently married women wives. However, the difference decreases “from 

15-44 years old have already occurred. This 1,111 births per 1,000 wives aged 40-44, to 140 

varies directIy by age with wives under age 20 births per 1,000 wives aged 15-19. The higher 
� 4 aduancdata 

total birth expectations of Negro wives is due to 

their already having had more children than 

white wives. 

Table 3 shows that the fertility of wives of 

Spanish origin or descent is more similar to that 

of Negro wives than to white wives. Compared 

with wives of other origins or descents, Spanish 

wives expect to have almost 25 percent more 

total births. This is due to their already having 

more children and expecting more children in 

the future than wives of other ongin. 

The greater the education of currently married women, the fewer total births they expect. 

This pattern is similar for each age group. The 

timing of births, however, is different for 

women with different amounts of education. 

Except for those with 1-3 years of high school, 

the more educated women expect more births 

in the future than their less educated counterparts, and have had fewer births in the past. 

Wives in the labor force expect fewer total 

births than wives not in the labor force. Those 

working full-time expect fewer total births than 

women working part-time. Women working 

full-time have also postponed a larger number of 

births than women either working part-time or 

who are not in the labor force. 

Currently married women whose family income is 150 percent or more of the poverty 

threshold expect to have fewer total births than 

women whose family income is less than 150 

percent of the poverty threshold. This pattern 

applies to all ages 20 years or older. There is no 

difference in birth expectations for women below 

the poverty threshold and those whose family income is 100-149 percent of the poverty threshold. 

Roman Catholic wives expect to have more 

total births than Protestant wives. Protestant 

wives, in turn, expect to have more total births 

than Jewish wives or wives of other or no religious identification. There is no difference in 

the timing of the births for Catholic, Protestant 

and Jewish wives because the pattern is apparent 

in both categories—children ever born and additional births expected. Catholic and Protestant 

wives who participate more frequently in religious activities expect more tots.I births by the 

end of their childbearing than do women of the 

same religious identification who participate less 

frequently. 

The older the woman was at the time of her 

first marriage, the fewer births she expects by 

the time she completes hex childbearing. The 

difference between women married at ages 20 to 

21 and those married at ages 22-24 years, however, is not statistically significant. The pattern 

of decreasing numbers of total births expected 

with increasing age at marriage is observed for 

most age groups. However, there is also a general 

pattern of increasing numbers of additional 

births expected with increasing age at marriage 

indicating a difference by age of marriage in the 

timing of childbearing. 

The timing of the first birth in relationship 

to marriage affects the total number of children 

a woman expects to have. Women who had a 

premarital birth expect to have 699 more births 

per 1,000 women tl%.n those whose first birth 

occurred after marriage. Except for women 

40-44 years old, there is no difference in the 

total number of births expected by wives whose 

first child was born within 8 months of marriage 

and those whose first child was born 8-14 

months after marriage. However, women who 

waited 

first child 

15 

have 

months 

significantly 

or more for 

lower 

the 

total 

birth 

birth 

of their 

ex­�

pectations than those having a birth sooner after 

marriage. Wives with no live births by the survey 

date expect fewer total births than wives with at 

least one birth, regardless of its timing. 

For all ages, women using contraception expect the same number of total births as women 

not using contraception. However, women who 

are using contraception have already borne more 

children. At ages 30 or older women using contraception expect to have more total births than 

women not using contraception. Among women 

who report that they are not using contraception, sterile women have had more births 

than other women expect to have; sterile women 

are older than other women not using contracept ion. Women who were pregnant, post 

partum, or trying to become pregnant at the 

date of interview are predominantly in the early 

years of their childbearing. While they expect 

about the same number of total births as women 

not using contraceptives, they have borne fewer 

children. Women sterilized for contraceptive reasons, or whose husbands have been sterilized, 

have borne more children than any other group 

of contracepting or noncontracepting women o 

expect to have. 
-----

o ackmeMa5 

Table 1. Number of currently married women 15-44 years old, number of children they have borne, minimum, maximum, and central 

number of births expected, and number of births desired per thousand, by race and age: United States, 1973 

Number of Children Minimum CentraI Maximum 

Race and age wives in ever births number births Births 

thousands born expected of births expected desirad 

expected 

o 

All races 

1544 years ............. 

15-19 years .................. 

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

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

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

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

4044 years .................. 

White 

15=44 years ............. 

15-19 years ....... ........... 

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

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

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

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

4044 years .................. 

Negro 

1544 years .. .......... . 

15-19 years .................. 

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

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

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

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

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

26,646 2,180 2,653 2,783 2,985 2,753 

1,028 479 2,047 2,376 2,684 2,644 

4,949 921 2,057 2,313 2,653 2,491 

6,063 1,651 2,250 2,445 2,696 2,530 

5,248 2,575 2,791 2,879 3,063 2,712 

4,632 3,054 3,155 3,183 3,313 3,036 

4,726 3,251 3,279 3,297 3,361 3,104 

24,249 2,139 2,607 2,737 2,933 2,749 

915 438 2,022 2,358 2,672 2,621 

4,469 875 2,025 2,283 2,612 2,484 

5,579 1,614 2,208 2,406 2,651 2,523 

4,768 2,523 2,737 2,821 2,998 2,688 

4,199 3,041 3,130 3,157 3,281 3,049 

4,320 3,172 3,198 3,215 3,276 3,119 

2,081 2,712 3,198 3,326 3,610 2,759 

96 820 2,197 2,498 2,777 2,692 

451 1,365 2,336 2,575 3,024 2,540 

417 2,147 2,749 2,922 3,295 2,627 

402 3,?60 3,447 3,534 3,782 2,844 

347 3,513 3,671 3,714 3,933 2,909 

367 4,255 4,303 4,326 4,413 2,960 

SYMBOLS 

Data not avaiIable —---

Category not applicable— . . . 

Quantity zero——-—-—— 

Quantity more than Obut less than 0.05— 0.0 

Figure does not meet standards of * reliability or precision 
6 aduancedata 

o 

Table 2. Number of children already born, additional births expected by timing, and percent total of births expected per 1,000 currently 

married women 1544 years old, by race and age: United States, 1973 

Additional births expected Total Parcent total of births expected 

Children Race and age births

already Within Within In all 

?xpected Already ompleted )ompleted 

born 2 years 5 years 

future 

occurred 

within within 

All races 

1544 years ........... .. 

15-19 years ....... ...... ..... 

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

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

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

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

4044 years .................. 

White 

1544 years ..... ........ 

15-19 years ......... ........ . 

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

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

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

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

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

Negro 

1544 years ............. 

15-19 years ............. ..... 

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

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

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

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

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

years 2 years 5 years 

2,180 153 447 603 2,783 78 84 94 

479 458 1,391 1,897 2,376 20 39 79 

921 283 1,049 1,392 2,313 40 52 85 

1,651 226 598 794 2,445 68 77 92 

2,575 104 223 304 2,879 89 93 97 

3,054 46 82 130 3,183 96 97 99 

3,251 15 26 47 3,297 99 99 99 

2,139 151 444 599 2,737 78 84 94 

438 467 1,406 1,920 2,358 19 38 78 

875 286 1,065 1,408 2,283 38 51 85 

1,614 224 594 793 2,406 67 76 92 

2,532 100 207 289 2,821 90 93 

3,041 43 76 116 3,157 96 98 

3,172 14 23 43 3,215 99 99 

2,712 157 459 613 3,326 82 86 95 

820 411 1,249 1,678 2,498 33 49 83 

1,365 255 930 1,210 2,575 53 63 89 

2,147 238 600 775 2,922 73 82 94 

3,160 119 310 374 3,534 89 93 98 

3,513 52 77 200 3,714 95 96 97 

4,255 21 41 71 4,326 98 99 99 
o admceMa7 

Table3. Number of total M~hsexpetied andchildren ever born perl,OOO currently married women 1544yeam old byageandby seIected characteristics: United States, 1973 

Selected characteristics 

All women ......... .......... .............. ............................ 

Origin 

Spanish ............................. ........ .................................. 

Education 

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

High school: 13years ................ ............ ........ ............ 

High school: 4 years ................................ .............. ..... 

College: 1-3 years ....... ...... ....... ....................... ............ 

College: 4 years or more .................. ............ ............... 

Labor force status 

Not in labor force ........... .......................... .................. 

In labor force ........... ........ .......................................... . 

Working full.time .............. .. .... .......... ..................... 

Working pati.time .............. .................................... 

Not working .......... .................... ............................ 

Poverty level income 

Below poverty income .......................... .. .................... 

100-149 percent poverty income ................................ 

150 percent poverty income or more ................. ......... 

Religion and religious participation 

� 

Protestant ................. ........ .............. ............................ 

More frequent ................................... .. ................... 

Less frequent ............................... ............. ............. 

Roman Catholic ....................... ................................... 

More frequent .......................................... .......... .... 

Less frequent .............................. ........ ................... 

Jawish .... ..................................................................... 

Other or none ............................... .......................... .... 

Age at first marriage 

Under 18 years ................ .................................. ......... 

18-19 years .. ........ ............................ ........................... 

20-21 yaars ..................................................... ............ 

22-24 years .. ................ ............................................... 

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

300r more years ......................... ............................... 

Timina of first birth 

Before marriage ..... .. .......................... ........ ................ . 

After marriage ........................................... ................. 

O-7 months ............................................................ 

8-14 months .. ...... ...................... ............................ 

15 or more months .................................. .............. 

No live births ...... ...... ...................... ............................ 

Contraceptive status 

Noncontraceptors ...X .. ............... ................................. 

Pregnant, post partum, seeking pregnancy ............. 

Sterile ................ .................................................... 

Other ................................ ........ ............................. 

Contraceptors ............................................................. 

0 Sterilization ~,,, ,UD ............................... ............ ................


..................... .................................. .........


Other methods ............ ...................... ...... ...............


1 Age in years 

Total 

I 15-19 I 20.24 i 25-29 I 3034 I 3539 ~ 4044 

Total births expected 

2,783 2,376 2,312 2,44 2,879 3,18: 3,297 

3,403 2,886 2,81 C 3,258 3*395 3,84C 3,840 

2,741 2,324 2,27S 2,394 2,854 3,118 3,267 

3,686 2,71 ! 3,134 3,27S 3,658 3,861 4,214 

3,148 2,26> 2,55S 2,877 3,365 3,565 3,654 

2,669 2,393 2,27f 2,38C 2,839 3,065 3,023 

2,544 2,36E 2,1 0s 2,297 2,568 2,971 “3,160 

2,302 . . 1331 2,11 E 2,317 2,385 2,898 

2,942 2,397 2,47S 2,634 3,032 3,348 3,480 

2,560 2,335 2,11 e 2,147 2,633 2,966 3,074 

2,511 2,39g 2,132 2,12E 2,519 3,028 3,021 

2,730 2~13 2,227 2~6E 2,836 2,907 3,314 

2,410 *1 ,455 1 ,50E 1,961 2,766 2,760 2,791 

3,501 2,466 2,641 3,09e 3,738 4,203 4,692 

3,564 2,319 2,363 3,230 3,930 4,477 4,799 

2,545 2,366 2,273 2,332 2,719 2,960 3,080 

2,710 2,246 2~60 2,402 2,798 3,088 3,198 

2,782 2,338 2,381 2,468 2,810 3,129 3,090 

2,644 2,182 2,195 2,341 2,787 3,034 3,324 

3,057 2,780 2,514 2,650 3,138 3,476 3,632 

3,225 2,804 2,626 2,725 3,284 3,630 3,795 

2,840 2,782 2,409 2,553 2,929 3,251 3,330 

2,356 *3,040 1,569 2,094 2,058 2,583 2,771 

2,257 2,020 2,117 2,002 2,553 2,680 2,586 

3,219 2,347 2,528 2$53 3,629 3,704 3,767 

2,862 2,413 2,283 2,527 3,038 3,430 3,671 

2,654 . . . 2,254 2,318 2,786 3,199 3,019 

2,551 . . . 2,194 2,253 2,432 2,831 3,064 

2,291 . . . . . . 2,039 2,225 2,273 2,638 

1,901 . . . . . . . . . 1,434 1,767 2,274 

3,672 2,358 3,131 3,279 3,889 4,140 4,481 

2,973 2,381 2,406 2,610 2,992 3,275 3,456 

3,226 2,294 2,435 2,691 3,493 4,049 4,678 

3,250 2,538 2,466 2,851 3,216 3,525 3,771 

2,693 2,401 2,346 2,453 2,630 2,890 3,009 

1,717 2,376 2,073 1,633 1,022 654 276 

2,740 2,543 2,589 2,542 2,680 2,987 2,956 

2,727 2,635 2,665 2,685 2,734 3,084 3,144 

2,897 . . . *409 2,118 2,520 3,152 3,044 

2,627 2,200 2,411 2,146 2,729 2,727 2,802 

2,801 2,251 2,202 2,406 2,948 3,267 3,503 

3,328 *1512 2,311 2,806 3,195 3,544 3,796 

2,563 2,214 2,184 2,338 2,851 3,439 3,508 

2,752 2,450 2,233 2,307 2,839 2,859 3,257 
---

8 admmeckita 

o 

Tabla 3. Number of total births axpected and children ever born per 1,000 currently married women 1544 years old by age and by selected characteristics: United States. 1973–con. 

[i Age in years 

Selected characteristics Total I 15-19 20-24 25-29 30-34 35-39 40-44 

Children ever born 

All women ............ ...... ........ .. ............................ 2,180 479 921 1,651 2,575 3,054 3,251 

—— Origin 

Spanish ... ........................................ ............................ 2,641 *674 1,268 2,404 2,932 3,612 3,574 

Other ... ....... ................. ........ .. ................................ ..... 2,149 459 897 1,604 2,558 2,998 3,233 

Education 

Less than high school .. ...... .. .. .... .. ...... .... .... .. .. ..... . ... .... . 3,210 810 1,832 2,627 3,358 3,640 4,146 

High schooi: 1-3 years ..... .. .. .... .. . .... .. ... .. .. .. .. .... .. .. ...... . 2,707 587 1,694 2,434 3,733 3,424 3,617 

High school: 4 years .. .. .. .. .. .... .. .. .... ... . ..... ... . .... .. . ...... ... 2,072 342 835 1,719 2,584 2,959 2,976 

College: lSyears .. .. ..... .. . .... ... .. .. .. .. .. ...... ... ... .. . . ..... ... . . 1,812 -.. 473 1,323 2,227 2,892 3,117 

College: 4 years or more . ...... .. .. ... ... .. .. .. .. .. ... ... .. .... .. ... . 1,470 . . . *155 730 1,770 2,220 2,855 

Labor force status 

Notin Iabor force .... ... . ... .. .. .. .. .. . ... .... .. .. .... .. ... ... .... . ..... 2,395 557 1,207 1,985 2,767 3,197 3,421 

In labor force .. .. .. .... .. .. .... .. . . .. .. .. ... .... ... . ..... .. . .... .. .. .. .. ... 1,877 324 580 1,124 2,267 2,865 3,042 

Working full.time ... .. .. .. .... .. .... .... .. .. .. .. .. .. ..... . . .. .. .. ... 1,731 282 498 1,042 2,153 2,908 2,983 

Working paW.time .... .. . .... ... ... .. .... .. ... ... .. .... ... .... .. .. .. 2,239 *455 937 1,432 2,498 2,836 3,294 

Not working .... .. .... .. ... ... .. .. .... .. .. .... .... . ..... .. .. .... . ... .. 1,931 *89 *514 944 2,293 2,670 2,762 

Poverty level income 

Below poverty income ... ... . .. ... ... .. .. .. .. .. .... .. .. .... .. .. ...... . 2,734 579 1,150 2,101 3,488 3,975 4,55 

100-149 percent poverty income .. .. .. .. .... .. . ..... .. .. .. .. . .. . 3,099 791 1,410 2,732 3,765 4,388 4,73 

150 parcent poverty income or more .... .. ... ... .. ... .... . .. .. 2,043 407 837 1,531 2,399 2,836 3,041@ 

Religion and religious participation 

Protestant. . .. .. .. .. .... ... ... .... .. .. .... .. .. .... .. . ... .... ... .... ... . ..... . 2,158 482 928 1,670 2,548 2,993 3,169 

More frequent ... ... .. .... .. .. .... ... ..... .. .. .. .. .. . . ..... . .. .... .... 2,287 551 959 1,747 2,646 3,040 3,041 

Less frequent ... . .. .... .... .. .... .. . ... .. ... ..... .. .. .... .. .. .... .. .. . 2,039 434 912 1,599 2,550 2,932 3,318 

Roman Catholic .. .. .. .... .. .. .... .. .. .... . ... ..... ... .. .... .. . ..... . ... .. 2,359 ’471 888 1,773 2,727 3,273 3,546 

More frequent . ..... .. .. .... .... .. ... . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .... 2,525 *283 677 1,732 2,903 3,425 3,729 

Less frequent . .... . ... .... ... ... .... .. .. .... ... . ... .. .. . .... .. .. ..... . 2,144 *589 1,089 1,820 2,475 3,051 3,209 

Jewish ... .. .. .. .... .. ..... . .. . ... .. .. .. .... .. .. .. .. . ... .. .. .. .. .. .... . .. .... ... 1,914 ’540 ““314 994 2,058 2,510 2,733 

Other or none ....... . .. ..... .. . ...... .. .. .. .. .. .. .... .. .. . .... . .... .... .. . 1,467 *479 1,035 1,025 2,103 2,471 2,510 

Age at first marriage 

Under 18 years ..... .. .... . ..... . ... .... .. .. .... ... .. ..... . ... .. .... ..... . 2,778 687 1,653 2,603 3,462 3,628 3,750 

18-19 years .. .. .. .. .... .. ... ... .. .... ... ... . ..... .. .. .... .. .. .... .. .... ... .. 2,266 *2 I 8 1,007 2,019 2,838 3,361 3,652 

20-21 years . ... . ... .. .. .. .. .. .. .. .. .... .. .. .... .. .. .... .. .. .. .... .. .. ... ... . 1,999 . . . 512 1,503 2,591 3,106 2,976 

22-24 years ... .. ...... .. .. .... .. .. .... .. .. ... ... .. .... ... .. ..... . . .. ... . .. .. 1,825 . . . *279 964 1,985 2,675 2,997 

25-29 years .. .. .. .. .. .. .. .. .. . ... .... .. .. .. .. .. .. ...... .. ..... ... . .... . .. ... 1,657 . . . . . . 654 1,476 1,963 2,573 

30 or more years . .. .... .. .. .. .. .... .. .... . .. ..... . .. ..... ... . .... ... . ... . 1,284 . . . . . . . . . *333 1,108 1,950 

Timing of first birth 

Before marriage ..... .. .. ... ... .. .. .. .. .. ..... . .. .. .. . ... .. .... .. .. ... .. .. 3,186 1,123 2,218 2,695 3,441 3,957 4,468 

After marriage ..... .. .. .... .. .. .... .. .. .... ... . .... .. .. ...... . .. .... .. . .. . 2,626 1,154 1,474 2,036 2,761 3,181 3,424 

O-7 months .. .. .. .. .... . ... ... . ... ..... . ... ... ... ... ... . .. .. ..... . .. ... 2,842 1,128 1,602 2,278 3,387 3,952 4,651 

8-14 months ... ...... . .. .... .. .. .... .. .. .. .. .. .. .... .. . ... ... .. .. .... . 2,966 1,139 1,561 2,361 3,039 3,419 3,733 

15 or more months .... .. . ... .. . ... .... .. .. .... .. .. ..... . .... ... .. . 2,317 1,228 1,325 1,774 2,309 2,806 2,980 

No live births ... .... ... .. ... . .. . ..... . . ..... ... .. .... .. .. ..... .. .. ..... .... . . . . . . . . . . . . . . . . . . . . . 

Contraceptive status 

~oncontraceptors ...... ........................................ ......... 1,825 ’305 824 1,223 1,985 2,628 2,839 

Pregnant, post partum, seeking pregnancy ............. 1,056 348 780 1,088 1,401 1,822 1,866 

Sterile ...... ............ .................................................. 2,897 *409 2,118 2,520 3,152 3.044 —,- Other. ... ... . .... .... .. .... ... . .... .. ... ... .... .. .. .. .. .... ... ... ... .. .. .. 2,166 “93 1,031 1,388 2,474 2,521 2,72 

Contraceptors ... . ... ...... .. .. .. .. .. .... .. .. .. .. .. .. .. ... .. ... .. .... . .. ... 2,335 611 960 1,820 2,779 3,236 3,49 

Sterilization . .. ... .. . . . . . . . . . .... ... .. . ....... .. .. ..... . .. .. .. .. .. ..... 

Pill, IUD .... .. .... .. .. .. . .. ... ..... .. ... ..... . .. .. ... . .. ..... . . .. . . . . . . . 

3,328 

1,832 

“1/812 

621 

2,311 

872 

2,806 

1,669 

3,195 

2,647 

3,544 

3,390 

3,79 m 3,506 

Other methods . .. .... .. .. . ... .... ..... ..... ..... ... .. .... . ... .. .. ... . 2,322 +503 830 - 1542 2,558 - 2811 - 3247 
........................... ...........................

admcedm9 

TECHNICAL NOTES 

DESIGN OF THE SURVEY: The National Survey of FamiIy Growth (NS FG), initiated in 

1971, is designed to provide data on fertility, 

family planning, and related aspects of maternal 

and child health. Field work for Cycle I was 

carried out by the National Opinion Research 

Center in 1973 and early 1974 with September 

13, 1973, as the midpoint of the interviewing. 

A multistage probability sample of women 

in the noninstitutional population of the conterminous United States was used. The sample 

of women eligible for the NS FG was between 

the ages of 15 to 44 years, inclusive, were currently married or previously married or were 

never man-ied but had natural children presently 

living in the household. A detailed description of 

the sampIe design will be presented in a forthcoming report “Sample Design, Estimation Procedures, and Variance Estimation for a National 

Survey of Family Growth.” 

�ELIABILITY OF ESTIMATES: Since the statistics presented in this report are based on a 

Table i. Approximate standard errors for estimated numbers of 

white and total women: 1973 National Survey of Family 

Growth 

Size of estimate 

50,000................................... 100,000................................. 200,000................................. 500,000................................. 1,000,000.............................. 2,000,000. ............................ 5,000,000.............................. 10,000,000 .
 20,000,000 .


Relative 

standard Standard 

error error 

30.0 15,000 

21.2 21,000 

15.0 30,000 

9.5 47,000 

6.7 67,000 

4.8 95,000 

3.0 151,000 

2.2 216,000 

1.5 311,000 

e 

sample, they may differ somewhat from the figures that would have been obtained if a 

complete census had been taken, using the same 

questionnaires, instructions, intervie~ving personnel, and field procedures. This chance difference 

between sample results and a complete count is 

referred to as sampling error. In addition, the 

results are also subject to nonsampling error due 

to respondent misreporting, data processing mistakes, and nonresponse. It is very difficult, if not 

impossible, to obtain accurate measures. of nonsampling errors. These types of errors were kept 

to a minimum by the quality control procedures 

and other methods incorporated into the survey 

design and administration. 

SampIing error, or the extent to which sampIes may differ by chance from a complete 

count, is measured by a statistic called the standard error of estimate. Approximate standard 

errors for estimated numbers and ratios from 

this survey are shown in tables I and II. 

The chances are about 68 out of 100 that an 

estimate from the sampIe would differ from a 

replete census by less than the standard error. 

he chances are about 95 out of 100 that the 

differences between the sample estimate and a 

Table 11. Estimated standard errors of the ratio of total births expected per 1,000 women: 1973 National Survey of Family 

Growth 

Estimated ratio 

8ase of ratio 

I ,000 !,000 :,000 $,000 5,000 

20,000............... 232 531 826 1,121 1,416 

50,000............... 147 336 523 709 896 

100,000............. 104 238 370 502 634 

200,000............. 74 168 262 355 448 

500,000............. 47 107 166 225 284 

1,000,000.......... 33 76 118 160 202 

2,000,000.......... 24 54 84 114 144 

5,000,000.......... 16 35 54 74 93 

10,000,000........ 12 26 40 54 68 

20,000,000........ 9 20 30 41 51 

complete count would be less than twice the 

standard error. The relative standard error is the 

ratio of the standard error to the statistic being 

estimated. In this report, numbers and percentages which have a standard error that is 

more than 25 percent of the estimate itself are 

considered “unreliable.” They are marked with 

an asterisk to caution the user but may be combined to make other types of comparisons of 

greater precision. 

In this report, terms such as “similar” and 

“the same” mean that any observed difference 

between two estimates being compared is not 

statistically significant. Similarly, terms such as– 
10 achncedata 

“greater,” “less,” “larger,” “smaller,’’etc., indicate that the observed differences are statistically significant. The normal deviate test with a 

0.5 level of significance was used to test all comDEFINITION 

Children ever born. –The number of children 

born alive to a woman. 

Additional births expected. –The number of 

children a woman expects to give birth to in the 

future, including current pregnancy, if applicable. Women who were sterile or married to 

sterile men were classified as expecting zero 

additional births. Those physically able to have 

births were asked whether they and their husbands intended to have any babies in the future 

and, if so, how many. Women who did not know 

whether they intended any future births, or did 

not know a particular number they intended to 

have, were asked for the smallest and largest 

numbers they expect to have. Women who reported a particular number of children they intended to have were asked how sure they were 

about having specifically that number. Those uncertain of having that specific number were 

asked for the maximum and minimum numbers 

they expect to have. 

For each woman, there is a maximum, minimum and central number of additional births 

expected. If a woman reported a specific 

number she intended to have, that was considered the central number she expected. If she 

was sure about it, that was also the minimum 

and maximum number she expected. For a 

woman who was not sure of having her intended 

number, the smallest and largest numbers she 

expected were her minimum and maximum numbers, respectively. For a woman who did not 

report any specific number of intended future 

births, the average of the smallest and the largest 

numbers expected became her central expected 

number. In this report, discussion of additional 

births expected refers to the central number unless specifically identified otherwise. Further discussion of this topic will be given in a forthcoming report in Series 23 of Vital and Health 

Statistics. 

Total births expected. –The number of 

children a woman expects to have by the time 

.9 

parisons. Lack of comment in the text between 

any two statistics does not mean the difference 

was tested and found not to be si~ificant. 

OF TERMS 

she completes her childbearing. This number is 

the sum of the children ever born and the additional births expected. Minimum, maximum and 

central numbers ,of total births expected are calculated by using the minimum, maximum and 

central additional births expected. Unless specified otherwise, references to total births expected refer to the central number. 

Births desired. –The number of children a 

woman would have if she could start life all over 

again and have just the number of children she 

wan ted, knowing other things would have 

turned out just about the way they did for her 

and her husband. 

Age.–The respondent’s age at her Iast birthday before the interview. � 

Age at first marriage. –The woman’s age at 

the time of her first marriage or commonlaw 

union. 

Con traceptive status. –Women were classified as “noncontraceptors” if they were pregnant, post partum (last pregnancy terminated 

less than two months before interview) or they 

and their husbands were not using contraceptives because she was trying to become pregnant, they or their husbands were sterile for other 

than contraceptive, reasons, or for some other 

reason. Women were classified as “contraceptors” 

if they or their husbands had had a sterilizing 

operation at least partly for contraceptive reasons, if they were using the pill, the IUD, or 

other methods of contraception. 

Education. –The highest grade of regular 

school the woman had completed at the survey 

date. 

Labor Force Status. –A woman is categorized as being in the labor force if she was 

working ftdl-time or part-time, had a job but was 

not at work because of temporary illness, vacation, or a strike, or if she was unemployed, 

laid off, or looking for work. A woman is clas 

sified as working full-time if she works 35 ore 

more hours a week. 
dmcdata 11 

e 

Marz”tal Status. –Marital status classifications 

are married, widowed, divorced, separated, or 

never married. Married persons include those 

who reported themselves as married or as informa.IIy married, such as living with a partner or 

commonlaw spouse. This classification includes 

those who are temporarily separated. for reasons 

other than maritzd discord such as vacation, illness, or Armed Forces. Persons who are separated legally or informally for reasons of marital discord are classified as separated. AU tables 

in this report are based upon currently married 

women or others whose marital status at the 

time of the interview was “married.” 

Poverty leveL –The poverty index ratio was 

czdculated by dividing the total family income 

by the weighted average threshold income of 

nonfarm residents, head under 65, based on the 

poverty leveIs shown in the U.S. Bureau of the 

Census, Current Population Reports, Series P-60, 

No. 98, “Characteristics of the Low-Income 

Population, 1973,” table A-3. This definition 

akes into account the sex of the family head 

d the number of persons in the family. Total 

family income includes income from aIl sources 

for zdl members of the respondent’s family. 

Race. –Classification by race of the woman 

interviewed, based on interviewer observation, 

was reported as Negro, white, or other. 

Religi”on and religious participation. –Women 

were asked whether they were Protestant, Catholic, Jewish or something else. Protestant includes most of the Christian groups other than 

Roman CathoIic. The “other” category includes 

non-Chnstian religions and no reIigion. 

Protestant women are classified as having 

more frequent religious participation if they attend religious services twice a month or more, 

and having Iess frequent participation if attendance is once a month or less. 

Catholic women are classified as having more 

frequent religious participation if they receive 

communion several times a year or more, and 

less frequent participation if they receive communion once a year or less. Sample reliability 

makes subclassification of Jewish or “other or 

none” reIi@ous categories by participation impractical. 

Spanhh on-p-n. –A respondent was classified 

as being of Spanish origin if she reported her 

origin or descent as Mexican, Chicano, Mexican 

Am eri can, Puerto Rican, Cuban, or other 

Spanish. 

Timing of first birth. –The first birth is classified as occurring before or after the first or 

ordy marriage. First births occurring after marriage are further classified by the number of 

months between marriage and the birth. 

* 
12


0


Previous issues of Advance Data From Vital and Health Statistics 

No. 1.	 Blood Pressure of Persons 6-74 Years 

of Age in the United States (Issued: 

October 18, 1976) 

No. 2.	 Hypertension: United States, 1974 

(Issued: November 8, 1976) 

No. 3.	 Height and Weight of Adults 18-74 

Years in the United States (Issued: 

November 19, 197 6) 

No. 4.	 Prevalence of Dermatological Diseases 

Among Persons 1-74 Years of Age, 

United States (Issued: January 26, 

1977) 

No. 5.	 A Comparison of Levels of Serum 

Cholesterol of Adults 18-74 Years of 

Age in the United States in 1960-62 

and 1971-74 (Issued: February 22, 

1977) 

U.S. DEPARTMENT OF HEALTH, EDUCATION,


Public Health Service


Health Resources Adrninlstration


National Center for Health Statlsti.s


Cennx Building


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HY.ttsvllle, Mawland 20782


OFFICIAL BUSINESS


PENALTY FOR PRIVATE USE, $300


HRA 77-1250 

TOreceiveWISDubkation rcwlarly. conhct 

the National Ckter for Hca~h St&tics by I Cal,in,k.msm I 

AND WELFARE 

No. 6. Dietary Intake of Persons 1-74 Years 

No. 7. 

No. 8. 

No. 9. 

of Age in the United States (Issued: 

March 30, 1977) 

Total Serum Cholesterol Level of 

Adults 18-74 Years of Age in the 

United States in 1971-74 (Issued: 

May 25, 1977) 

Total Serum Cholesterol Level of 

Children 417 Years of Age in the 

United States in 1971-74 (Issued: 

July 11, 1977) 

Wanted and Unwanted Births Reported 

by Mothers 15-44 Years of Age in the 

United States in 1973 (Issued: August 

10, 1977) 

GPO 9!9-170 

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