|電話號碼抽樣方法是從住宅電話簿中首先以隨機方法抽取「種籽」號碼，再 以加一減一加二減二的方法產生另一組號碼，然後在混合後再過濾重覆號 碼，再以隨機排列方式排次成為最後樣本。|
Surveys on the overall performance of the HKSAR Government are conducted at least once a month, by telephone interviewers under close supervision.
All these surveys are conducted by telephone interviewers under close supervision. Target population of these surveys are Cantonese speakers in Hong Kong of age 18 or above.
The sample size of all these surveys are more than 500 successful cases each time. Since May 2000, it has been increased to more than 1000, and weighted according to gender-age distribution of the Hong Kong population.
Telephone numbers are first selected randomly from telephone directories as seed numbers. Another set of numbers is then generated by using the plus/minus one/two method. Duplicate numbers are then screened out, and the remaining numbers mixed in a random order to become the final sample.
Upon successful contact being made with a target household, one member of the household is selected among those present using the "next birthday" rule.