One of the questions when discussing the usefulness of Web-based surveys is whether they gain the same response rates compared to other modes of survey data collection. A common perception exists that in general, Web survey response rates are considerably

lower, but such unsystematic anecdotal evidence could be misleading and does not provide any useful quantitative estimate. Meta-analytic procedures synthesizing controlled experimental mode comparisons could give accurate answers, but to the best of our

knowledge, such research syntheses have not been conducted so far. To overcome this gap, we conducted a meta-analysis of 45 published and unpublished experimental comparisons between Web and other survey modes. On average, Web surveys yield an 11% lower response rate compared to other modes (the 95% confidence interval is confined by 15% and 6% on the disadvantage of the Web mode). This response rate difference is systematically influenced by the sample recruitment base (lower difference for panel members as compared to one-time respondents), the solicitation mode chosen for Web surveys (larger difference for postal mail solicitation compared to e mail), and the number of contacts (the more contacts, the larger the difference in response rates between modes). No significant influence on response rate differences could be revealed for the type of mode Web surveys are compared to, the type of target population, type of sponsorship, whether or not incentives were offered, and the year the studies were conducted. Practical implications are discussed.