Telephone survey with manual questioning was adopted. All Cantonese speakers among Hong Kong residents aged 18 or above were defined to be the target population of the survey. To minimize sampling bias, the following sampling technique was adopted:
Telephone numbers were first drawn randomly from the residential telephone directories as "seed numbers", from which another set of numbers was generated using the "plus/minus one/two" method, in order to capture the unlisted numbers. Duplicated numbers were then filtered, and the remaining numbers were mixed in random order to produce the final telephone sample.
When telephone contact was successfully established with a target household, one person was selected from all those present using the "next birthday" rule. A total of 1,002 respondents were successfully interviewed between 12-23 March 2001. The overall response rate was 63.1%
To improve the representativeness of the results, all figures presented in the report have been weighted according to the gender and age distributions of the Hong Kong population according to the 1996 By-Census data.
The researcher is aware that the POP Team is part of The University of Hong Kong, which is one of the universities rated by the respondents. As a precaution to eliminate any possible bias due to desirability effect, all respondents were explicitly told at the beginning of the interview that the POP Team was an independent research team, and the respondents should simply report honestly what they felt.