The Design Effects of Voting Advice Applications: Comparing Methods of Calculating Results

In election times more and more voters have consulted Voting Advice Applications (VAAs), such as smartvote in Switzerland, Wahl-O-Mat in Germany or EU Profiler across EU Member States. The potential impact of these online tests on election outcomes is substantial and hence it is important to study the effects of their design. This paper focuses on an important element of the design, namely the method used to calculate the match between voters and parties. More specifically, we examine the use of alternative (implicit or explicit) spatial models and metrics. The analyses are based on the actual answers given by users of one of the most popular VAAs in Europa, StemWijzer in the Netherlands. The results indicate that the advice depends strongly on the spatial model adopted. A majority of the users of StemWijzer would have received another advice, if another spatial model had been used. These findings have important implications for the design of future VAAs