Table 2.

Response Rates by Data-Collection Mode, Case Flow, and Eligibility Group

Data-collection mode	Eligibility group by case flow
	High			Medium			Low
	Phone-first	Mail-first	p-value	Phone-first	Mail-first	p-value	Phone-first	Mail-first	p-value
CATI
N	1,899	1,353		1,193	891		1,597	978
Completed topical interviews	385	230		193	105		79	35
Screener response rate	23.9	22.1	0.2365	22.9	16.2	0.0002	30.1	19.9	< 0.0001
Interview completion rate	53.3	46.3	0.0167	55.5	53.6	0.7176	65.8	47.3	0.0107
SAQ
N	1,306	1,835		858	1,258		1,017	1,707
Completed topical interviews	337	664		180	347		92	172
Screener response rate	21.5	27.3	0.0002	21.3	29.4	< 0.0001	34.2	40.7	0.0008
Interview completion rate	100.0	99.7	N/A	100.0	99.7	N/A	100.0	100.0	N/A
Combined
N	1,899	1,835		1,193	1,258		1,597	1,707
Completed topical interviews	722	885		373	447		171	205
Screener response rate	39.7	45.1	0.0012	40.4	43.8	0.0950	54.7	56.3	0.2930
Interview completion rate	68.6	77.4	< 0.0001	71.1	83.1	< 0.0001	81.0	84.4	0.3508

Note.—Regarding the SAQ interview completion rate, the REACH U.S. mailing included the screening and topical interview in the same packet. Nearly all cases that completed and returned the screening interview also completed the topical interview, hence the high interview completion rate. REACH U.S. coded a SAQ as complete if the respondent had answered at least the first question from every section of the survey and had provided enough information to determine respondent race/ethnicity and age category. P-values could not be calculated for the SAQ interview completion rate since there was no variation among the phone-first cases.