Int. J. Environ. Res. Public Health 2011, 8 2.7. Outcome Measures 1679 Cessation outcome measures include: (1) making a quit attempt; (2) quitting among the entire baseline sample; and (3) quitting among those who made a quit attempt (successful quit attempt). All outcome measures are based on self-report and are described below. Attempts to stop smoking were assessed in the follow-up survey waves among current smokers at baseline by asking: ―Have you made any attempts to stop smoking since we last talked with you?‖ Those responding ―yes‖ were categorized as having made at least one quit attempt between survey waves. Individual smoking status at time of interview is determined using self-reported smoking status. ‗Current smokers‘ were respondents who reported smoking daily, weekly, or monthly at the time of the survey. ‗Former smokers‘ were respondents who reported quitting in the time since last contact. This includes respondents who reported quitting: (1) in the last month, (2) 1 to 6 months ago, or (3) 6 to 12 months ago. This was used for two outcomes, quit at follow-up and successful quitting, which includes quitting at follow-up among only those who reportedly made a quit attempt. This measure of ―successful quitting‖ represents the success rate, or the proportion of quit attempts that result in actual cessation. 2.8. Statistical Methods The ITC project is subject to relatively high levels of attrition due to the longitudinal design. Therefore, all analyses have been weighted to adjust for loss to follow-up, using longitudinal survey weights. The weighting techniques and procedures developed and used in the ITC-4 study have been published elsewhere [23]. All statistical analyses were completed using SPSS version 14.0. Multivariate logistic regression analysis was used to examine whether price minimizing behaviors at baseline were predictors of cessation outcomes at follow up. Statistical tests for interaction were performed to examine the joint effects of various price avoidance behaviors and socio-economic status (low, moderate, or high) using multivariate logistic regression modeling. All models presented in this manuscript are adjusted for the covariates described above. Sub-analyses of long-term cessation outcomes at wave 7 were performed among 3,387 participants who were present at waves 5, 6 and 7, and were current smokers at wave 5 and wave 6. This analysis examines whether long-term use of low or untaxed tobacco sources or tax status changes between waves 5 and 6 were associated with cessation outcomes at follow-up using multivariate logistic regression modeling. Tests for interaction were also performed using the same methods as described above. 3. Results 3.1. Univariate Analyses and Demographic Characteristics of the Study Population Baseline characteristics of the study population overall and stratified by country are given in Table 1. Between wave 5 and wave 6, 37.4% reported making a quit attempt and 10.8% were quit at the time of the wave 6 survey. Among the 3 wave cohort (wave 5 to wave 7), 37.5% of current smokers at wave 6 made quit attempts between waves 6 and 7, and 10.2% were quit at the follow-up.