Contact informationBack


  Date of survey : June 18 to 19, 2008
  Survey method : Random telephone survey conducted by real interviewers
  Target population : The target population of this survey was the local working population of age 25 or above who had traveled outside of Hong Kong in the past 2 years.
  Sampling method :
The contacts 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.
  Sample size : 558 successful cases
  Overall Response rate :

67.2%
  Std. sampling error : Less than 2.1 percentage points. In other words, the sampling error for all percentages was less than plus/minus 4.2percentage points at 95% confidence level.

Table 1 Breakdown of contact information of the survey

 

Frequency

Percentage

Respondents' ineligibility confirmed

3,925

 29.2%

Fax/ data line

400

3.0%

Invalid number

2,722

20.2%

Call-forwarding/ mobile/ pager number

60

0.4%

Non-residential number

392

2.9%

Special technological difficulties

37

0.3%

No eligible respondents

314

2.3%

 

 

 

Respondents' ineligibility not confirmed

4,240

 31.5%

Line busy

631

4.7%

No answer

2,902

21.6%

Answering device

97

0.7%

Call-blocking

38

0.3%

Language problem

192

1.4%

Interview terminated before the screening question

312

2.3%

Others

68

0.5%

 

 

 

Respondents' eligibility confirmed, but failed to complete the interview

4,734

35.2% 

Household-level refusal

13

0.1%

Known respondent refusal

6

0.0%

Appointment date beyond the end of the fieldwork period

4,304

32.0%

Partial interview

46

0.3%

Miscellaneous

365

2.7%

 

 

 

Successful cases

558

4.1% 

 

 

 

Total

13,457

100.0% 

Table 2 Calculation of effective response rate

   Effective response rate
= [ Successful cases / (Successful cases + Partial interview + Refusal cases by eligible respondents* + Refusal cases by prorated-eligible respondents^) ]
= [ 558 / ( 558+ 46 + 19 + 312[(558 + 46 + 19) / (558 + 46 + 19 +314)]) ]*
= 67.2%
* Figure obtained by prorata