TABLE 5-5 Comparisons of Population Estimates for Children

 

Census Count/DA Estimate

Age Group

2000

1990

Under 5 years

0.972

0.963

5–9 years

0.997

0.965

10–14 years

1.025

0.988

Total under 10 years

0.985

0.964

Total under 15 years

0.998

0.972

SOURCE: Data from U.S. Census Bureau.

consistently significantly higher sex ratios at ages 18–29 and 30–49 than shown in the 2000 census or the A.C.E., for which sex ratios for blacks at these ages are similar and below what one would expect. In other words, both the 2000 census and the A.C.E. show net undercounts of black males relative to females at these ages, continuing a pattern exhibited in earlier censuses; see Table 5-4. This pattern is believed to be due to the lower propensities for black men to be counted in any census or survey than black women (“correlation bias”). Sex ratios for nonblacks ages 18–29, on the other hand, are somewhat higher in the A.C.E. than in DA, which was not the case in 1990.

Yet another component that can shed some light on the comparison of DA with the census are the estimates for people under age 15. The DA estimates at these ages are less affected by the uncertainties associated with the immigration component, especially undocumented immigrants. Table 5-5 shows the ratios of census to DA estimates for 1990 and 2000 (base estimate) for age groups under age 15. If one assumes that DA is fairly reliable at these younger ages, either the 2000 census had higher coverage at these ages than in 1990 or there was more overcounting (duplication) than in the 1990 census.

CONCLUSIONS

Demographic analysis has strengths as well as weaknesses in its processes and underlying assumptions for developing estimates of the expected total population for groups. For 2000, it would appear that the demographic estimates are weakest, or at least most uncertain, for two elements of major importance: total population for use in measuring overall net undercount and differential undercount for blacks and nonblacks. The DA estimates of sex ratios by race and of younger ages are informative, but limited in usefulness for measuring the comparative coverage of the three data sets—census, A.C.E., and DA.



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