Indicators of Marriage and Fertility in the United States from the

American Community Survey: 2000 to 2003

Tallese Johnson and Jane Lawler Dye

Population DivisionThis report is released to inform interested parties of ongoing research

and to encourage discussion of work in progress. The views expressed on (statistical, methodological, technical, or operational) issues are those of

the authors and not necessarily those of the United States Census Bureau.

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Benefits of Using the American Community Survey (ACS) for Analyzing Marriage and

Fertility Indicators

• Trends in marriage, cohabitation and fertility have all contributed to changing family structure in the United States.

• ACS is unique in that it can explore the relationship between changing family structure and socio-economic characteristics at national and lower levels of geography annually.

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Benefits of Using the American Community Survey (ACS) for Analyzing Marriage and

Fertility Indicators

• The following family structure variables will be explored in this presentation:– Median age at First Marriage, – Married-couple and Opposite-Sex

Unmarried Partner Households, and– Women with a Birth in the Last Year.

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Benefits of Using the American Community Survey for Analyzing Marriage and Fertility

Indicators

• There are no reliable current data on marriage from the National Vital Statistics System, especially for states.

• There are no questions about cohabitation on either the marriage or birth certificates.

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Benefits of Using the American Community Survey (ACS) for Analyzing Marriage and

Fertility Indicators • A large sample size, and 3 to 5 year

averages permit the description of smaller populations such as women who had a birth in the last year and unmarried-partner households.

• The ability to analyze state level data is of importance to policy makers at both the national and local levels.

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MethodsSurveys

• In order to approximate the reliability of the fully implemented ACS 2005 survey of 3 million housing units, 4 years (2000-2003) of ACS data were used.

Year Initial Sample Size

2003 828,590

2002 742,409

2001 858,058

2000 890,698

Total 3,319,755

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MethodsStatistical Tests

• For comparisons of the median age at first marriage differences larger than 0.1 years were determined to be different at the 90-percent confidence level.

• All comparisons of household and fertility data in the presentation have taken sampling error into account and are significant at the 90-percent confidence level.

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Median Age at First Marriage

• The estimated median age at first marriage (MAFM) is an important indicator of the changing American family.

• The rise of the MAFM since 1970 signals the increase in the number of young people who choose to delay marriage. Marital delays contributed to the growth in the number of non-family households.*

• Marriage at older ages can be linked to an increase in the likelihood of non-marital births.*

* Jason Fields. America’s Families and Living Arrangements: 2003, Current Population Reports, P20-553, United States Census Bureau: Washington, DC, 2004.

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Median Age at First Marriage

• The United States Census Bureau has provided annual estimates of the median age at first marriage from the Current Population Survey (CPS) since 1947. The same procedure is used to estimate the median age at first marriage from ACS.

• Although age at first marriage is not asked on the ACS, an indirect method estimates the median age at first marriage based on the proportion of people who were ever married for 5-year age groups ranging from 15 to 54.*

* Shryock and Siegel, The Methods and Materials of Demography, (1973 revised edition), Vol. 1, pp. 291-295.

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Median Age at First Marriage

• On average, from 2000 to 2003, the median age at first marriage (MAFM) for men and women was 27 and 25 years old, respectively.

• The MAFM for both men and women is generally higher in states in the Northeast than the national average.

• The MAFM for both men and women is lower in states in the Midwest, West and South than the national average.

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Coupled Households

• Marriage and cohabitation are also important indicators/predictors of the changing American family.

• Marital status is used in establishing and evaluating programs and policies that relate to welfare, family leave, childcare, and other areas of work and family life.*

• The likelihood of cohabitation has increased due to delayed marriage.*

* Jason Fields. America’s Families and Living Arrangements: 2003, Current Population Reports, P20-553, United States Census Bureau: Washington, DC, 2004.

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Coupled HouseholdsMarried-Couple Households

• In the United States, 50.6% of households were composed of married couples.

• States in the Midwest, West, and some states in the Northeast and the South had a higher percentage of married couples than the national average.

• Scattered states in the West and the South had a lower percentage of married couples as compared with the national average.

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Coupled HouseholdsUnmarried-Partner Households

• In the United States, 5.0% households were composed of unmarried partner households.

• States in the West, and a few states in the Northeast had a higher percentage of unmarried partner households compared with the national average.

• Most states in the South had a lower percentage of unmarried partner households compared with the national average.

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Coupled HouseholdsSummary

• 50.6% of households were maintained by married couples; and 5.0% were maintained by unmarried partners.

• States in the Midwest and West had a higher percentage of married couple households compared with the national average.

• Scattered states in the West and the South had a lower percentage of married couples as compared with the national average.

• States in the West and Northeast had a higher percentage of unmarried partner households than the national average.

• Most states in the South had a lower percentage of unmarried partner households compared with the national average.

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Women with a Birth in the Last Year

• Like the National Center for Health Statistics (NCHS) data, the ACS can show marital status and age of women with a birth in the last year.

• However, unlike NCHS, ACS can provide socio-economic information (poverty status, labor force participation, citizenship, and language skills) about fertility indicators.

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Comparison of ACS and NCHS Fertility Rates

Differences in data collection:

• NCHS fertility data are from total counts of births occurring in each state in a calendar year.

• ACS fertility data cover a period from the surveymonth to the same month in the prior year (e.g. June 2002-June 2003). This results in slightly more than 12 months of data and hence a larger number of births than that tabulated on a 12-month calendar year used by NCHS (January to December).This generally results in overall higher fertility rates in the ACS with the exception of rates for Hispanics where no statistical differences were noted.

• Differences in data collection procedures between ACS and NCHS may also affect the comparability of fertility estimates by race and Hispanic origin of the mother as ACS respondents self-identify their race and origin.

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69.6

63.3

73.378.2

70.9

93.5

65.5

58.0

68.8

58.2

65.1

95.8

Total Non-Hispanic White Non-Hispanic Black American Indian Asian or Pacific Islander Hispanic (of any race)

ACS

NCHS

Births per 1,000 women 15 to 44 years

Source: U.S. Census Bureau, American Community Survey 2002-2003, Census Supplementary Survey 2000-2001 and National Vital Statistics Reports; Vol. 52, No. 19 and Vol. 53, No.9 Hyattsville, Maryland: NCHS.2004.

Comparison of ACS and NCHS Fertility Ratesby Race and Hispanic Origin for Women,

4-Year Average: 2000-2003

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Comparison of ACS and NCHS Age-Specific Fertility Rates

Differences in age-groups:

• ACS fertility data are presented by the age of the mother at the time of the survey.

• NCHS fertility data are presented by the age of the mother at the time of her birth.

• On average, ACS fertility age groups represent mothers’ ages 6 months after their child’s birth. For example, ACS teenagers include some women who had a child at age 14 but exclude some women who had a child at age 19 who had turned 20 by the time of the survey.

– This difference tends to produce underestimates of fertility at younger ages (the loss of births to the teenage group by 19 years old is not offset by the gain of births by women 14 years old) and overestimates of fertility at older ages.

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Comparison of ACS and NCHS Age-Specific Fertility Rates, 4-Year Average: 2000 to 2003

Note: Since the age of the mother in the ACS is at the time of the survey and not at the birth of her child, this contributes to age-specific fertility differences between the two data sets in extreme age groups.

35.6

109.3116.0

100.6

50.2

14.2

44.4

105.5114.1

92.5

41.4

8.3

15-19 20-24 25-29 30-34 35-39 40-44Age Groups

ACS NCHS

Source: U.S. Census Bureau, American Community Survey 2002-2003, Census Supplementary Survey 2000-2001 and National Vital Statistics Reports; Vol. 52, No. 19 and Vol. 53, No.9 Hyattsville, Maryland: NCHS.2004.

Births per 1,000 women 15 to 44 years

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Comparison of ACS and NCHS State Fertility Data

Differences in data collection:• ACS data are presented by the residence of the woman at the

time of the survey, while NCHS data are presented by the residence of the woman at the time of her birth.

• Sampling variability among the different states may affect the estimates from the ACS while NCHS estimates that 99 percent of births occurring in the United States are registered in their system.

• For some populations with small numbers of people, large sampling variances may fail to produce differences among states. – The migration of mothers to another state after childbirth may

affect the comparability between two data sets.

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Comparison of ACS and NCHS Fertility Rates for Women, 4-Year Average: 2000-2003

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Source: United States Census Bureau, American Community Survey 2002-2003, Census Supplementary Survey 2000-2001 and National Vital Statistics Reports; Vol. 52, No. 19 and Vol. 53, No.9 Hyattsville, Maryland: NCHS.2004.

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Comparison of ACS and NCHS Fertility Data for Selected Characteristics of Women with a Birth in

the Last Year

• Data on the characteristics of mothers with infants can be used to evaluate the needs and requirements of health and maternal programs.

• Several characteristics have been identified as being associated with children living in poverty*:– Being born to a teenage mother– Being born to a mother who is never married.

• ACS data are presented by the marital status of the woman at the survey date while NCHS data are presented by the marital status of the woman at the time of the child’s birth.– Since some women in the ACS may have married after their child’s

birth, this may contribute to lower percentages of births being born to unmarried women in the ACS.

* The Annie Casey Foundation, 2004 Kids Count Data Book, (Baltimore, MD:2004), p.38.

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Comparison of ACS and NCHS Fertility Indicators for Births to Teenagers and

Unmarried Mothers

*Among women with a birth in the last year Unmarried women includes widowed, divorced, and never-married women.Source: United States Census Bureau, American Community Survey 2002-2003, Census Supplementary Survey 2000-2001 and National Vital Statistics Reports; Vol. 52, No. 19 and Vol. 53, No.9 Hyattsville, Maryland: NCHS.2004.

Percent of Births to Unmarried Mothers, 4 Year Average: 2000-2003

29.1

33.8

ACS NCHS

Percent

Percent of Births to Women 15 to 19, 4 Year Average: 2000-2003

7.7

11.0

ACS NCHS

Percent

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Women with a Birth in the Last Year Unmarried Women

• In the United States, 29.1% of women who had a birth in the last year were unmarried.

• Most states in the South had a higher percentage of mothers who were unmarried compared with the national average.States in the West, Midwest and Northeast had lower percentages of mothers who were unmarried compared with the national average.

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Women with a Birth in the Last YearTeenagers

• In the United States, 7.7% of women who had a birth in the last year were teenagers in the United States.

• States in the South, and a few states in the West had a higher percentage of mothers with a birth in the last year who were teenagers compared with the national average.

• States in the Northeast were composed of a lower percentage of mothers with a birth in the last year who were teenagers compared with the national average.

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Women with a Birth in the Last Year Poverty

• In the United States, 23% of women who had a birth in the last year were below the poverty level.

• Most states from Arizona to North Carolina had a higher percentage of mothers with a birth in the last year who were below the poverty level compared with the national average.

• A block of states from Nevada in the West to Indiana in the Midwest, and most states in the Northeast had a lower percentage of mothers with a birth in the last year who were below the poverty level compared with the national average.

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Women with a Birth in the Last Year Married Mothers in Poverty

• In the United States, 12% of married women who had a birth in the last year were below the poverty level.

• A run of states ranging from Washington to North Carolina had a higher percentage of married mothers with a birth in the last year who were below the poverty level compared with the national average.

• Many states ranging from Nevada in the West to Maine in the Northeast had percentages of married mothers with a birth in the last year who were below the poverty level that were not statistically different from the national average.

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Women with a Birth in the Last YearUnmarried Mothers in Poverty

• In the United States, 50% of unmarried mothers with a birth in the last year were below the poverty level.

• Most states in the South, and some states in the West had a higher percentage of unmarried mothers with a birth in the last year who were below the poverty level compared with the national average.

• No distinct geographical patterns were found among the lower percentage of unmarried mothers with a birth in the last year who were below the poverty level compared with the national average.

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Women with a Birth in the Last YearPovertySummary

• 23% of all women who had a birth in the last year were below the poverty level; 12% of all married mothers who had a birth in the last year were below the poverty level; 50% of all unmarried mothers who had a birth in the last year were below the poverty level.

• A higher percentage of married mothers with a birth in the last year who live in the West and South were below the poverty level compared with the national average.

• Married mothers with a birth in the last year who live in the Midwest and the Northeast had a lower percentage living below the poverty level compared with the national average.

• Most states in the South, and some states in the West had a higher percentage of unmarried mothers with a birth in the last year who were below the poverty level compared with the national average.

• No distinct geographical patterns were found among the lower percentage of unmarried mothers with a birth in the last year who were below the poverty level compared with the national average.

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Women with a Birth in the Last YearLabor Force

• In the United States, 56% of mothers with a birth in the last year were in the labor force.

• Most states in the Midwest, and some states in the Northeast and South had a higher percentage of mothers with a birth in the last year who were in the labor force compared with the national average.

• States in the West had a lower percentage of mothers with a birth in the last year who were in the labor force compared with the national average.

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Women with a Birth in the Last YearMarried Mothers in the Labor Force

• In the United States, 54% of married women who had a birth in the last year were in the labor force.

• Most states in the Midwest, and some states in the Northeast and South had a higher percentage of married mothers with a birth in the last year who were in the labor force compared with the national average.

• Most states in the West had a lower percentage of married mothers with a birth in the last year who were in the labor force compared with the national average.

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Women with a Birth in the Last Year Unmarried Mothers in the Labor Force

• In the United States, 60% of unmarried women who had a birth in the last year were in the labor force.

• States in the Midwest and South had a higher percentage of unmarried mothers with a birth in the last year who were in the labor force compared with the national average.

• States in the West had a lower percentage of mothers with a birth in the last year who were in the labor force compared with the national average.

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Women with a Birth in the Last YearMothers in the Labor Force

Summary

• 56% of all women who had a birth in the last year were in the labor force; 54% of all married mothers with a birth in the last year were in the labor force; 60% of all unmarried mothers with a birth in the last year were in the labor force.

• Across all groups, mothers with a birth in the last year who live in the Midwest had higher labor force participation rates than recorded nationally.

• Across all groups, mothers with a birth in the last year who live in the West had lower labor force participation rates than recorded nationally.

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Women with a Birth in the Last Year Language and Citizenship

• In the United States, 8% of all mothers with a birth in the last year who spoke another language at home, spoke English ‘Not well’ or ‘Not at all’.

• In the United States,14.6% of mothers with a birth in the last year were non-citizens.

• States in the West, Texas, and Illinois had a higher percentage of mothers with a birth in the last year who spoke English ‘Not well’ or ‘Not at all’ and were non-citizens compared with the national average.

• States in the Midwest and South had a lower percentage of mothers with a birth in the last year who spoke English ‘Not well’ or ‘Not at all’ and were non-citizens compared with the national average.

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Geographical Correlates of Fertility and Family Indicators

• Fertility and family indicators show marked geographical patterns.

• How are they related to each other?

• Simple correlations show how these patterns can be analyzed among geographic units.

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Findings

Type of Household Estimated Median Age at First Marriage

Men Women

Married Couple Households -0.607* -0.693*

Unmarried Partner Households 0.327* 0.268*

Pearson’s Correlations of Median Age at First Marriage with Type of Household

•Geographic differences with the median age at first marriage are strongly related to household composition.•States with a high median age at first marriage tend to have higherproportions of unmarried couple households and lower proportions of married couple households.

* Statistically significant at the 90% confidence level.

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Findings

Characteristics of Women with Infants Percent below the Poverty Level

Percent in the Labor Force -0.403*

Percent who speak English ‘Not well’ or ‘Not at all’ 0.064

Percent who were Non-citizens 0.039

Percent who were Teenagers 0.612*

Percent who were Unmarried Mothers 0.713*

Pearson’s Correlations of Percentage of Women with a Birth In the Last Year who are Below the Poverty Level with Selected Socioeconomic Characteristics

•States with relatively high proportions of women with infants below the poverty level were related to other socio-economic factors such as:

Low levels of labor force participation,High proportion of births among teenagers, andHigh proportion of births among unmarried mothers.No relationship with percent who speak English ‘Not well’ or ‘Not at all’ and who were non-citizens.

* Statistically significant at the 90% confidence level.

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Conclusion

• The benefits of using the ACS to study marriage and fertility:– A large sample size;– The ability to analyze both state and

national level data;– The ability to analyze the relationship

between socio-economic and fertility and marital indicators.

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American Community Survey Data

• For more information about the ACS sample design, estimation methodology, and accuracy of the data please go to the following website:www.census.gov/acs/www/UseData/Accuracy/Accuracy1.htm