Table 2. Pooled estimates for awareness, previous use, current use and healthier perception of e-cigarette using D+L random effect models.

	Awareness of e-cig		Previous use of e-cig		Current use of e-cig		Healthier perception of e-cig
	N	Pooled estimate(95%CI)	N	Pooled estimate(95%CI)	N	Pooled estimate(95%CI)	N	Pooled estimate(95%CI)
Subgroups
Current smokers	10	0.719(0.575,0.863)	15	0.272(0.188,0.356)	7	0.168(0.072,0.263)	7	0.631(0.521,0.741)
Former/ever smokers	8	0.599(0.437,0.761)	15	0.157(0.012,0.272)	7	0.182(0.077,0.287)	6	0.568(0.384,0.751)
Never smokers	8	0.468(0.268,0.668)	12	0.025(0.011,0.036)	5	0.012(0.004,0.021)	2	0.491(0.432,0.550)
Current and ever smokers	5	0.581(0.299,0.864)	9	0.247(0.153,0.341)	6	0.107(0.047,0.168)	3	0.464(0.235,0.693)
Smokers and non-smokers	10	0.645(0.497,0.792)	16	0.150(0.081,0.219)	13	0.086(0.051,0.122)	1	0.548(0.540,0.556)
Users of e-cigarette							5	0.379(-0.005,0.763)
Awareness of e-cigarette							2	0.520(0.498,0.543)
Overall	41	0.612(0.515,0.708)	67	0.168(0.140,0.196)	38	0.111(0.092,0.131)	26	0.526(0.425,0.626)