Target respondents of the study were Cantonese-speaking working population of Hong Kong of age 18 or above. Telephone interviews were conducted by interviewers under close supervision. All data were collected by our interviewers using a Computer Assisted Telephone Interview (CATI) system which allowed real-time data capture and consolidation. To ensure data quality, on top of on-site supervision, voice recording, screen capturing and camera surveillance were used to monitor the interviewers' performance.
The fieldwork was conducted during the period of May 11 to 20, 2009. A total of 1,006 Hong Kong working people of age 18 or above were successfully interviewed. The overall effective response rate of this survey was 74.6%, and the standard sampling error for percentages based on this sample was less than 1.6 percentage points. In other words, the sampling error for all percentages is less than plus/minus 3.2 percentage points at 95% confidence level.
To ensure representativeness of the findings, the data collected have been adjusted according to provisional figures obtained from the Census and Statistics Department regarding the gender-age distribution of the Hong Kong working population of age 15 or above (Jan-Mar 2009). All analyses in this study are based on the weighted data.