This was a random telephone survey conducted by telephone interviewers under close supervision. Telephone numbers were selected randomly from the database provided by commissioning body. All data were collected by our interviewers using a Web-based Computer Assisted Telephone Interview (Web-CATI) system which allowed real-time data capture and consolidation. To ensure data quality, on top of on-site supervision and random checking, voice recording, screen capturing and camera surveillance were used to monitor the interviewers’ performance.
The target population of this survey is Hong Kong residents aged 18 or above who are credit card users and have not settled their credits by full payment for at least once before. When interviewers reached the target respondents successfully, the eligibility of target respondents would be confirmed before the survey started.
The survey was conducted during the period of July 31 to August 12, 2013. 504 respondents were successfully interviewed. The effective response rate was 74.9%, and the standard sampling error for percentages based on this sample was less than 2.2 percentage points. In other words, the maximum sampling error for percentages was less than plus/minus 4.5 percentage points at 95% confidence level.