Panel attrition is a major problem in long-term panel studies. While the design of the German National Educational Panel Study adult survey--combining biannual competency tests with regular face-to-face interviews--is highly innovative, such a design could raise respondent burden and thus potentially increase panel attrition and nonresponse bias. To test this possibility, we use an experimental split questionnaire design administering two tests to one half of the respondents but only one test to the other half. Analyzing the effects of these different experimental settings on response behavior shows that even though those assigned to the longer test variant had no higher probability of refusing to participate in the survey, they were significantly more likely to apply alternative strategies for not taking the tests. The results also show that not only test avoidance but also low test performance has negative consequences for survey participation in later waves.