In this article, we present the results of three question design experiments on inter-item correlations, which tested a grid design against a single-item design. The first and second experiments examined the inter-item correlations of a set with five and seven items, respectively, and the third experiment examined the impact of the question design on inter-item correlations of follow-up questions. We found that the inter-item correlations in grid designs were higher for both the set of five and seven items than for questions in a single-item design. Additionally, the inter-item correlations of the set of follow-up questions were higher if the preceding set of questions was presented in a grid. According to the findings of the present research, respondents seem to apply the interpretative near means related heuristic when answering grid questions, and also when answering follow-up questions preceeded by grid questions.