Census-based measures of fertility, mortality, and migration

1. Census-based measures of fertility, mortality, and migration Hist 5011

2. Fertility: Yasuba 1962 • Measure ratio of women aged 15-49 to children aged 0-4 for each state (or county) • Correlate with characteristics of state (e.g. land availability, sex ratio, ethnicity)

3. Fertility: Coale and Zelnik 1963 • Begin with single-year age distribution • Adjust for mortality • Adjust for census underenumeration • Yield: number of births in each year, back to 1800 • Suggested very early fertility decline

4. Limitations • No information on marital fertility • No age-specific rates (cannot look at stopping vs. spacing) • Cannot study differentials between population subgroups (e.g. different occupations)

5. Microdata allows own-child fertility analysis • Retherford and Cho, 1978 • Calculate mean number of children of each age living with mothers of each age • Adjust mean upwards to reflect mortality of children, underenumeration, and children residing without mothers • Yields estimates of age-specific marital fertility

6. Simple own-child approach • Even if we can make rough estimates of adjustments for whole populations, we cannot do so for population subgroups • Therefore, adjustments make no sense when studying fertility differentials • Simple own-child approach uses no adjustments: just measure mean children under 5 with mothers of each age.

7. Children ever born • Limitation: we don’t know when they were born • Best for study of completed fertility • Can calculate cohort parity distributions for older women • Allows cohort-parity analysis (David and Sanderson 1987)

8. Mortality: Two-Census methods • Get two adjacent censuses • Adjust population counts at each age for immigration, emigration, and changes in net underenumeration • Subtract to estimate number of deaths • Divide by midpoint of population to estimate age-specific death rates • Rough estimates only, since effects of adjustments are large

9. Mortality: Children-ever-born and children surviving • Calculate percent of children born surviving by age of mother • Standardize or focus on a particular age group • Can be used to study differentials • With fancier techniques, can be used to estimate age-specific death rates for young people (Preston and Haines 1991)

10. Migration: Net migration estimates from aggregate data • Eldridge and Thomas 1960 • Similar to two-census mortality estimation • Get age distributions by state • Adjust for mortality and differential underenumeration • The remaining difference between time periods is net migration • Result: slow upward trend in migration since 19th century

11. Migration: Using birthplace information • Calculate percent of native-born persons residing out of their state of birth • Works especially well for lifetime migration (Kelly Hall and Ruggles forthcoming)

13. Migration: Record linkage • Thernstrom 1963 and many others • Ferrie 2004 • New 1880 linkage project

15. Migration: Using children present • Can be tricky • Easiest measure, if you have enough cases: just look at persons who have children of a particular age • Large potential for selection bias

16. Migration: residence 5 years ago • Good since 1940 U.S., 1960s or 1970s in other countries • Focus on recent migration • Allows many methods