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Supplementing CAPI with CATI in a nationally representative Health Survey – effect on non-response. Michael Davidsen, Ola Ekholm Copenhagen, Denmark. Plan. The Danish Health and Morbidity Programme Design of the 2005 survey Response rate and CATI supplement Interpretation problems
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Supplementing CAPI with CATI in a nationally representative Health Survey – effect on non-response Michael Davidsen, Ola Ekholm Copenhagen, Denmark
Plan • The Danish Health and Morbidity Programme • Design of the 2005 survey • Response rate and CATI supplement • Interpretation problems • Comparisons of groups • Discussion and conclusion
The Danish Health and Morbidity Survey Programme • Nationally representative health interview surveys of adult (age 16+) Danes • Questions on health, symptoms, illness, ilness behaviour, life style, use of health care and much more (www.si.folkesundhed/susy) • General surveys conducted 1987, 1994, 2000 and 2005
The survey 2005 • Based on a random sample from the Danish Civil Person Register • Data collection from May 1. 2005 – February 17. 2006 (293 days) • Initially only interview by CAPI • SFI-SURVEY responsible for interviews
Invitation and interview • Written invitation, letter of introduction • Interviewer send letter and establish contact • Interview in the home of the respondent • Interviewer require more persons to interview.
Sample • Strata defined by 5 Danish regions • 3.000 interviews with response rate 70% • Two subsamples:1. a re-re-interview of persons invited in 1994 and supplemented twice by young persons2. a random sample ensuring adequate regional sizes
Demands • Overall response rates: 70% • Regional response rates: 70%, capital 64% • 21,832 person invited • 4,688 capital; 4,286 other regions
CATI supplement • Telephone contact to ’soft’ refuser, not met and out of town endorsed • Only 3 regions • Only by few ’super-interviewers’ • January and February 2006 • Same questionairre as with CAPI
CATI supplement • Based on a pilot study of 40 persons with positive response rate. • Information on ’soft refusers’ not available • CATI response rate cannot be calculated • Estimate based on pilot and information from SFI-SURVEY: 20%
Discussion and conclusion I • CATI supplement designed to improve response rate • Reasonable success late in data collection • Some conflicting interests when data collection company has interest in improving response rate
Discussion and conclusion II • CATI seems to ’catch’ young, men and unmarried