title: The utility of online panel surveys versus computer-assisted interviews in obtaining substance-use prevalence estimates in the Netherlands.
abstract: OBJECTIVE
  Rather than using the traditional, costly method of personal interviews in a general population sample, substance-use prevalence rates can be derived more conveniently from data collected among members of an online access panel. To examine the utility of this method, we compared the outcomes of an online survey with those obtained with the computer-assisted personal interviews (CAPI) method.
  
  
  METHODS
  Data were gathered from a large sample of online panellists and in a two-stage stratified sample of the Dutch population using the CAPI method.
  
  
  METHODS
  The Netherlands. Participants  The online sample comprised 57 125 Dutch online panellists (15-64 years) of Survey Sampling International LLC (SSI), and the CAPI cohort 7204 respondents (15-64 years).
  
  
  METHODS
  All participants answered identical questions about their use of alcohol, cannabis, ecstasy, cocaine and performance-enhancing drugs. The CAPI respondents were asked additionally about internet access and online panel membership. Both data sets were weighted statistically according to the distribution of demographic characteristics of the general Dutch population.
  
  
  RESULTS
  Response rates were 35.5% (n = 20 282) for the online panel cohort and 62.7% (n = 4516) for the CAPI cohort. The data showed almost consistently lower substance-use prevalence rates for the CAPI respondents. Although the observed differences could be due to bias in both data sets, coverage and non-response bias were higher in the online panel survey.
  
  
  CONCLUSIONS
  Despite its economic advantage, the online panel survey showed stronger non-response and coverage bias than the CAPI survey, leading to less reliable estimates of substance use in the general population.
authors: Radboud University, Behavioural Science Institute, Nijmegen, the Netherlands. r.spijkerman@pwo.ru.nl
authors: Renske
authors: R
authors: Spijkerman
authors: Ronald
authors: R
authors: Knibbe
authors: Kim
authors: K
authors: Knoops
authors: Dike
authors: D
authors: Van De Mheen
authors: Regina
authors: R
authors: Van Den Eijnden
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D015982:Bias; D003201:Computers; D005260:Female; D006306:Health Surveys / Q000191:economics* / Q000379:methods*; D006801:Humans; D020407:Internet; D007406:Interview, Psychological / Q000379:methods; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D019966:Substance-Related Disorders / Q000453:epidemiology*; D055815:Young Adult