Web-based surveys are increasingly perceived as a well-accepted data collection methodology. However, not enough is known about those people who are willing to participate but do not respond in the first survey. In 2009 an experiment was conducted to test how monetary incentives affect participation rates in the second survey wave, particulary with regard to those, who did not participate in the first survey wave.

In our study we used the German General Social Survey (ALLBUS) as a sampling frame. ALLBUS respondents with Internet access were asked to participate in the online survey. Those willing to participate were then invited by email.

In the second survey wave these people were randomly assigned to five incentive conditions: prepaid, postpaid, lottery, donation to charity and no incentive. To test the effects of monetary incentives on response rates we compare (1) those who participated in both surveys with those (2) who participated in the second but not in the first survey. We will report first results and discuss their implications for participation and attrition in online panel surveys.