Many studies on electronic voting evaluate their usability in the context of simple elections. Complex elections, which take place in many European countries, also merit attention. The complexity of the voting process, as well as that of the tallying and verification of the ballots, makes usability even more crucial in this context. Complex elections, both paper-based and electronic, challenge voters and electoral officials to an unusual extent. In this work we present two studies of an electronic voting system that is tailored to the needs of complex elections. In the first study we evaluate the effectiveness of the ballot design with respect to motivating voters to verify their ballot. Furthermore, we identify factors that motivate voters to verify, or not to verify, their ballot. The second study also addresses the effectiveness of the ballot design in terms of verification, but this time from the electoral officials' perspective. Last, but not least, we evaluate the usability of the implemented EasyVote prototype from both the voter and electoral official perspectives. In both studies we were able to improve effectiveness, without impacting effi-This project (HA project no. 435/14-25) is funded in the framework of Hessen ModellProjekte, financed with funds of LOEWE Landes-Offensive zur Entwicklung Wissenschaftlichkonomischer Exzellenz, Frderlinie 3: KMU-Verbundvorhaben (State Offensive for the Development of Scientific and Economic Excellence).