TY  - JOUR
PY  - 2013//
TI  - Examining non-response bias in substance use research-Are late respondents proxies for non-respondents?
JO  - Drug and alcohol dependence
A1  - Studer, Joseph
A1  - Baggio, Stéphanie
A1  - Mohler-Kuo, Meichun
A1  - Dermota, Petra
A1  - Gaume, Jacques
A1  - Bertholet, Nicolas
A1  - Daeppen, Jean-Bernard
A1  - Gmel, Gerhard
SP  - 316
EP  - 323
VL  - 132
IS  - 1-2
N2  - BACKGROUND: Non-response is a major concern among substance use epidemiologists. When differences exist between respondents and non-respondents, survey estimates may be biased. Therefore, researchers have developed time-consuming strategies to convert non-respondents to respondents. The present study examines whether late respondents (converted former non-participants) differ from early respondents, non-consenters or silent refusers (consent givers but non-participants) in a cohort study, and whether non-response bias can be reduced by converting former non-respondents. METHODS: 6099 French- and 5720 German-speaking Swiss 20-year-old males (more than 94% of the source population) completed a short questionnaire on substance use outcomes and socio-demographics, independent of any further participation in a cohort study. Early respondents were those participating in the cohort study after standard recruitment procedures. Late respondents were non-respondents that were converted through individual encouraging telephone contact. Early respondents, non-consenters and silent refusers were compared to late respondents using logistic regressions. Relative non-response biases for early respondents only, for respondents only (early and late) and for consenters (respondents and silent refusers) were also computed. RESULTS: Late respondents showed generally higher patterns of substance use than did early respondents, but lower patterns than did non-consenters and silent refusers. Converting initial non-respondents to respondents reduced the non-response bias, which might be further reduced if silent refusers were converted to respondents. CONCLUSION: Efforts to convert refusers are effective in reducing non-response bias. However, converted late respondents cannot be seen as proxies of non-respondents, and are at best only indicative of existing response bias due to persistent non-respondents.<p />  <p>Language: en</p>
LA  - en
SN  - 0376-8716
UR  - http://dx.doi.org/10.1016/j.drugalcdep.2013.02.029
ID  - ref1
ER  -