Table 1

Sample characteristics of the Tobacco Promotion Impact Study (TPIS)

	2010 (n=2000)		2011 (n=2010)		2012 (n=2003)		2013 dual-frame (n=2807)			2013 landline (n=2001)
	N	Per cent	N	Per cent	N	Per cent	N	Per cent	p Value	N	Per cent	p Value
Age in years									0.950			0.974
12–15	669	32	649	32	619	32	833	31		684	31
16–19	826	31	833	30	855	30	1046	31		799	31
20–24	505	37	528	38	529	38	928	39		518	39
Sex									1.00			1.00
Female	975	49	990	49	992	49	1325	49		980	49
Male	1025	51	1021	51	1011	51	1482	51		1021	51
State									1.00			1.00
NSW	1000	50	1004	50	1000	50	1407	50		1001	50
QLD	1000	50	1000	50	1000	50	1400	50		1000	50
SES									0.015			0.011
Low	557	28	497	25	578	29	735	28		536	26
Mod–high	1443	72	1514	75	1425	71	2056	72		1465	74
Smoking status									<0.001			<0.001
Never	1178	56	1278	61	1276	61	1769	60		1376	64
Experimenter	476	25	448	24	471	25	599	22		382	21
Former	53	4	42	3	36	2	70	3		36	3
Current	293	16	243	13	220	12	369	16		207	12
Smoking susceptibility*									0.074			0.075
Non-susceptible	941	81	999	79	968	76	1383	79		1071	79
Susceptible	237	19	279	21	308	24	386	21		305	21
Cigarettes per day†
<2	136	43	112	44	104	44	183	47	0.781	106	48	0.767
≥2	177	57	144	56	131	56	207	53		116	52
Friends smoke M (SD)	1.27 (1.60)		1.10 (1.51)		1.05 (1.47)		1.11 (1.52)		<0.001	0.93 (1.41)		<0.001
House smoke M (SD)	0.52 (0.86)		0.47 (0.86)		0.49 (1.01)		0.51 (0.99)		<0.001	0.42 (0.82)		0.048

Ns unweighted, %s are weighted; p values from χ² tests for differences between proportions or ANOVA tests for differences between means.
*Never smokers.
†Smokers.
M, Mean; NSW, New South Wales; QLD, Queensland; SES, Socioeconomic Status (based on postal code).