In this project, we perform a user study to evaluate the effectiveness of Social Choice-Based Explanations for Group Recommender Systems in different complex scenarios, whose complexity is determined by the number of group members, the number of possible items, and the diversity between group members' preferences. The collected answer, properly anonymized, are collected in this dataset. Information on the experiment are available in the preregistration document, which can be accessed, together with the R script for reproducing the performed statistical analyses, at the link: https://osf.io/3dcht/