Contact information返回

Date of survey	:	18/3-1/4/2010
Survey method	:	Telephone survey conducted by telephone interviewers
Target population	:	local working population aged 18 to 65 with a minimum monthly personal income of HK$5,000 and being covered by an MPF scheme
Sampling method	:	The contacts were successfully established with a target household, one target respondent was selected. If more than one subject had been available, selection was made using the "next birthday rule" which selected the person who had his/her birthday next from all those present.
Sample size	:	1,001 successful cases
Effective Response rate	:	65.2%
Std. sampling error	:	Less than 1.6%

Table 1 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) ]
= [ 1,001 / 1,001 + 65 + 27+ 698[(1,001 + 65 + 27) / (1,001 + 65 + 27 + 636)]* ]
= 65.2%

*Figure obtained by prorata

Table 2 Breakdown of contact information of the survey

	Frequency	Percentage
Respondents' ineligibility confirmed	12,102	42.3%
Fax/ data line	1,084	3.8%
Invalid number	9,168	32.0%
Call-forwarding/ mobile/ pager number	140	0.5%
Non-residential number	1,018	3.6%
Special technological difficulties	56	0.2%
No eligible respondents	636	2.2%

Respondents' eligibility not confirmed	6,848	23.9%
Line busy	308	1.1%
No answer	5,039	17.6%
Answering device	146	0.5%
Call-blocking	142	0.5%
Language problem	458	1.6%
Interview terminated before the screening question	698	2.4%
Others	57	0.2%

Respondents' eligibility confirmed, but failed to complete the interview	8,692	30.3%
Household-level refusal	10	0.0%
Known respondent refusal	17	0.1%
Appointment date beyond the end of the fieldwork period	8,478	29.6%
Partial interview	65	0.2%
Miscellaneous	122	0.4%

Successful cases	1,001	3.5%

Total	28,643	100.0%