Current study is a cross-sectional retrospective telephone survey based on questionnaires. In total, 5,104 subjects will be randomly selected for a telephone interview. The subjects will be categorized into three groups, i.e. never smokers (1,700), ex-smokers (1,700) and current smokers (1,704). They will be required to answer a questionnaire via telephone. All data shall be collected using a Computer Assisted Telephone Interview (CATI) system, which allows real-time data capture and consolidation. All interviews shall be conducted anonymously. Analysis of survey data will aim to identify current opinion on tobacco control policies and implications for future policies. Analyses will be controlled for confounding variables as required by stratification into sub-groups based on important pre-defined characteristics and/or by multivariate analysis. Comparison with past trends and, where possible, extrapolation of future trends will be explored. Weights will be applied to adjust for the sex and age of Hong Kong population, and to handle the over-sampling issues of current smokers. The data analysis will be conducted by statisticians.