Response Rates

Longitudinal Cohort Study

Screening

A stratified probability sample of 80 neighborhoods was selected from the 343 defined neighborhood clusters. Next, block groups were selected at random within each of the sample neighborhoods. A complete listing of dwelling units was collected for all sampled block groups. Pregnant women, children, and young adults in seven age cohorts (birth, 3, 6, 9, 12, 15, and 18 years) were identified through in-person screening of approximately 40,000 dwelling units within the 80 NCs. The screening response rate was 80 percent.

Wave 1 Response Rates

Children within six months of the birthday that qualified them for the sample were selected for inclusion in the Longitudinal Cohort Study. A total of 8,347 participants were identified through the screening. Of the eligible study participants, 6,228 were interviewed for an overall response rate of 75%.

Wave 1 Response Rates by Cohort

Wave 2 Response Rates

Of the 6,228 respondents from Wave 1, 16 were deceased by Wave 2, leaving 6,212 eligible for participation in the study. Of the eligible respondents, 5,338 participated in the Wave 2 interview for an overall response rate of 85.93%.

Wave 2 Response Rates by Cohort

Wave 3 Response Rates

Of the 6,212 eligible participants for Wave 2, nine were deceased by Wave 3, leaving 6,203 eligible participants in the study. Of the eligible respondents, 4,850 participated in the Wave 3 interview for an overall response rate of 78.19%.

Wave 3 Response Rates by Cohort