Table 1

Total numbers of invites and responses by strata and disposition.

	Stratum 1: 15–17 listed (n=1 89 993)			Stratum 2 18–21 listed (n=2 31 403)			Stratum 3 (Not Listed) (n=8 72 405)			Strata 1–3 Combined
	15–17 years	18–21 years	Total	15–17 years	18–21 years	Total	15–17 years	18–21 years	Total	Grand total
No. invited ABS sample units	114 013	75 980	189 993	32 553	198 850	231 403	384 635	487 770	872 405	1 293 801
No. completed screener (1)			5960			7189			27 315	40 464
No. confirmed study eligible (2)	2713	1799	4512	736	4302	5038	1451	1881	3332	12 882
No. consented (3)	2265	1744	4009	623	4180	4803	1266	1842	3, 108	11 920
I=complete interviews (1.1)	2054	1480	3534	570	3500	4070	1142	1511	2653	10 257
P=partial interviews (1.2)	211	264	475	53	680	733	124	331	455	1663
R=refusal and break off (2.1)	448	55	503	113	122	235	185	39	224	962
NC=non-contact (2.2)	0	0	0	0	0	0	0	0	0	0
O=other (2.0, 2.3)	0	0	0	0	0	0	0	0	0	0
Calculating e: e is the estimated proportion of cases of unknown eligibility that are eligible	0.7	0		0.65	0		0.12	0
UH=unknown household (3.1)	0	0	0	0	0	0	0	0	0	0
UO=unknown other (3.2–3.9) (4)	110 154	73 194	183 348	31 420	192 061	223 481	372 418	472 217	844 635	1 251 464

The reference to ABS refers to ‘address-based sample.’ The invited sample units consisted of addresses from the USPS Delivery Sequence File.
(1) Completed Screener: Completed the screener and have been determined as ineligible or eligible for the survey. Ineligible households are those in which there are no age-eligible persons. (2) Eligible: Eligible households are those in which an age-eligible child (ages 15–17 years) or adult (ages 18–21 years), was determined and selected to complete the survey. (3) Consented: Selected household member agreed to participate in the survey. For selected survey takers who were 15–17 years, the parent or legal guardian provided consent, and also agreed to have their teen come to the computer/screen, ahead of the teen providing their consent.