Factors included in adjustment weight | Factors not included in adjustment weight | |||||
Survey design element | % Women AOR (95% CL) | % White AOR (95% CL) | % Age 18–34 y AOR (95% CL) | % Hispanic AOR (95% CL) | % Income <$15000 AOR (95% CL) | % Married AOR (95% CL) |
County level† | ||||||
BRFSS response rate (ref≥60%) | ||||||
<40% | 2.11 (1.10 to 4.09)‡ | 0.31 (0.11 to 0.88) | 2.16 (1.09 to 4.27) | 0.97 (0.30 to 3.19) | 2.94 (0.51 to 17.13) | 0.41 (0.13 to 1.25) |
40–60% | 1.04 (0.90 to 1.20) | 0.76 (0.62 to 0.94) | 0.92 (0.81 to 1.04) | 1.32 (1.07, to .64) | 1.23 (0.92 to 1.65) | 0.84 (0.69 to 1.01) |
Data collection method (reference contracted out) | ||||||
In-house | 1.24 (0.93 to 1.67) | 0.49 (0.23 to 1.05) | 1.57 (1.00 to 2.47) | 1.02 (0.31 to 3.36) | 0.57 (0.18 to 1.81) | 1.00 (0.57 to 1.76) |
Sampling fraction (ref≤median) | ||||||
>Median (0.14) | 1.02 (0.80 to 1.31) | 0.76 (0.32 to 1.82) | 1.00 (0.65 to 1.55) | 0.70 (0.26 to 1.90) | 6.10 (1.68 to 22.19) | 0.70 (0.38 to 1.28) |
Number of call attempts (ref≤5 call attempts) | ||||||
>5 call attempts | 0.88 (0.63 to 1.23) | 1.00 (0.46 to 2.17) | 1.59 (1.02 to 2.49) | 0.82 (0.29 to 1.90) | 1.44 (0.53 to 3.89) | 1.29 (0.68 to 2.44) |
↵* Robust polytomous logistic regression used controlling for Census region and telephone coverage (results not reported). The outcome variable was BRFSS overestimates Census (BRFSS prevalence adjusted for NR/NC >2.5% points higher than Census– reference category) versus BRFSS underestimates Census (BRFSS prevalence adjusted for NR/NC >2.5% points lower than Census) versus BRFSS approximates Census (BRFSS prevalence adjusted for NR/NC within 2.5% points of Census). Analyses comparing underestimates to overestimates shown.
↵† Number of counties available for county-level analyses varied due to missing data and minimum sample size requirements (gender: n=732; race: n=730; age: n=732; ethnicity: n=729; income: n=638; marital status: n=730).
↵‡ Interpreted as relative to counties with BRFSS response rates ≥60%, counties with BRFSS response rates <40% had twice the odds of under versus overestimating % women.