Target respondents of the study were Cantonese-speaking 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 November 1 to 14, 2007. A total of 1,010 Hong Kong citizens of age 18 or above were successfully interviewed. Among them, 25 were patients of urinary stone and 70 were family members of such patients. As shown from the calculation in Appendix I, the overall response rate of this survey was 67.6% (Table 2), 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 3.1 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 population in mid-2007. All analyses in this report are based on the weighted data.