Table 2 Regression coefficients showing main effect of country (at baseline and across waves) and interaction between country and wave on reported endorsement of light beliefs

	Baseline country differences (wave 1)	Overall country effect (across four waves)	Effect sizes (compared with wave 1)†
	Baseline country differences (wave 1)	Overall country effect (across four waves)	Wave 2	Wave 3	Wave 4
Canada	−0.476***	−0.087***	0.007	0.040**	0.001
US	−0.272***	−0.051***	0.033*	−0.035*	−0.103***
Australia	−0.207***	−0.027***	0.042*	0.010	−0.069***
UK	Reference	Reference	0.033*	−0.154**	−0.050**

Regression coefficients were adjusted for age, sex, ethnicity, baseline income, baseline education, cigarette per day at each wave, smoking status at each wave, recentness since quitting at each wave, belief that filter reduces harm at each wave, and also baseline belief about harmfulness of light cigarettes. Main effect for country, wave (not shown in table) and their interaction was significant at p<0.001;
*p<0.05; **p<0.01; ***p<0.001.
†A negative coefficient indicates a decline, while a positive coefficient indicates an increase, in level of endorsement of the light beliefs (relative to that of the baseline wave).