Table I.

NCHS Sample Selection Process

Survey Stage:	Stage 1		Stage 2	Stage 3	Total
Phone Number Source:	RDDa	Cell Phone List	Hispanic surnames b	RDDa
Targeted Eligibility Criteria:c	None	None	Self-Identified Hispanic	Self-Identified African American
A. Total number fielded	4,649	2,748	791	3,000	11,188
B. Not Eligibled	2,124	1,526	319	1,709	5,678
C. Unknown Eligibility e	744	1,096	170	1,101	3,111
D. Known Eligible	1,781	126	302	190	2,399
E. Completed Surveys	666	79	157	120	1,022
F. Partially Completed Surveys	13	2	13	6	34
G. Eligibility Ratef	45.6%	7.6%	48.6%	10.0%	29.7%
H. Response Rate g	32.0%	38.7%	44.2%	42.0%	31.8%

^aRDD = Random Digit Dial. Numbers were pre-screened to be working, non-business phone numbers. All phone number lists were purchased from a vendor, Marketing Systems Group (M-S-G), Genesys Division.

^bPhone numbers listed to persons with Hispanic surnames

^cRespondents were eligible for participation in all three stages if they were an adult resident of Davidson County, Tennessee. In stages 2 and 3, participants were additionally screened for race and ethnicity in order to identity eligibility for the oversampled groups.

^dPhone numbers were classified as not eligible if the number was disconnected, the caller could confirm that the number was not associated with a housing unit (i.e. a business or institution), or if the caller could confirm that the number was associated with a housing unit where no adult residents of Davidson County resided. Cell phone numbers were considered ineligible if the answering respondent indicated that he or she also had a residential landline. Phone numbers were ineligible in stages 2 and 3 if the answering adult did not self-identify as Hispanic or African American.

^eThe eligibility of a phone number was classified as unknown if the caller could not confirm that a number was associated with a housing unit (as opposed to a business) or if the caller was unable to determine whether the respondent was eligible because the respondent did not complete screening procedures, including refusals, breakoffs, and hang-ups [AAPOR 2011].

^fEligibility rate is used to estimate the proportion of unknown eligibility cases that are actually eligible. We have calculated this value as: D/(B+D)

^gResponse rate is based on Response Rate 4 as defined by the American Association of Public Opinion Research [AAPOR 2011]. This definition assumes that a proportion of respondents whose eligibility could not be determined would have been eligible to participate (see Eligibility Rate). Response Rate 4 is calculated as: (E + F)/(D+G*C).