Int. J. Environ. Res. Public Health 2011, 8 1685 Participants who continued to use low and untaxed sources at waves 5 and 6 were also 47% less likely to report cessation at wave 7 (OR = 0.53, 95% CI: 0.29–0.97). Those who reported switching from full taxed sources to low or untaxed sources also appear to be less likely to report cessation at wave 7, although this failed to reach statistical significance. Conversely, respondents who reported switching from low or untaxed sources to full taxed sources appear to be more likely to quit smoking at wave 7, although again this was marginally non-significant. No significant interactions were present for differing purchase locations and SES on making a quit attempt or cessation at wave 7. 4. Discussion Data from this study indicate that a sizeable percentage of smokers from four high-income countries engage in behaviors aimed at obtaining lower priced cigarettes, by purchasing cheaper tobacco brands, utilizing low or untaxed tobacco retail outlets, using self-made (RYO) tobacco products, or purchasing tobacco in bulk (cartons). These price minimizing behaviors may decrease the public health benefits that are had from increasing cigarette prices through taxation, as engaging in price minimizing behaviors were associated with decreased likelihood of both making quit attempts and reporting cessation at follow-up. Overall, there does not appear to be a statistically significant interaction between socio-economic status (SES) and purchasing patterns on cessation outcomes. Although respondents with low SES differentially use varying types of price minimizing behaviors [24] the findings presented here suggest that the relationship between using price minimizing behaviors and cessation outcomes does not vary by SES. Therefore, tobacco control policies aimed at decreasing use or eliminate the price differentials between lower priced and full priced cigarettes should have equivalent effects on all segments of the market (i.e., without regard to SES groups). For all price minimizing behaviors examined, it appears that use inhibits cessation outcomes. However, it is important to examine and understand how each price minimizing behavior affects the specific cessation outcomes. This study indicated that purchasing from low or untaxed sources overall has a negative effect on cessation, but does not appear to inhibit respondents from making quit attempts. However, the opposite results were obtained using previous ITC data from waves 1 and 2 [7]. This study, which also assessed use of low or untaxed sources on cessation outcomes, found that use was associated with making fewer quit attempts but use was not associated with cessation [7]. One such explanation for this discrepancy over time could be due to the relatively small proportion of smokers who purchased from low or untaxed sources in previous waves as use was only reported by less than 1% in AU, 3.1% in CA, 4.8% in the US, and 15.3% in the UK. Use of discount or generic brand cigarettes at last purchase was associated with a reduced cessation success rate among those who attempted to quit. Similar to using low or untaxed sources, results of this study showed that using discount or generic brand cigarettes did not inhibit smokers from making quit attempts. Although not statistically significant, the point estimate associated with overall cessation in the current study was in the predicted direction, suggesting that use of discount brands may also reduce overall cessation. A previous study of US adults by Cummings, et al (1997) concurs, finding that use of discount or generic brands was associated with a 21% reduction in cessation at