Party Proximities in Voting Advice Applications – Identifying Structural Breaks in Data from the German Wahl-O-Mat

Voting Advice Applications (VAAs), such as the German Wahl-O-Mat (WOM), have been examined extensively by researchers in various ways. Here, a subset of research uses data from the Wahl-O-Mat to investigate party relations. While these investigations focus on a limited number of WOM editions, I explicitly investigate the persistence of party relations in the WOM in a broad statistical analysis over 63 editions of the WOM in this exploratory research paper. At first glance, I find that intuitive differences in the overall proximities are observable. However, while many arguments exist that corroborate the suitability of the WOM data for the investigation of party relations, I identify statistically significant lower proximities for the six largest German parties in WOM editions from 2009 onward. Based on a review of changes in the design framework of the WOM and comparative data analyses based on the Chapel Hill Expert Survey and the Manifesto data set, these lower proximities are apparently linked to changes in the design of the WOM. As a result, I discuss the general ability of data from the WOM to give reliable insights into party relations. I argue that the WOM might roughly represent overall party relations but, due to a non-proportionality in the shift of the distances, potential design changes have distorting impacts on the relations between parties that make comparisons between different editions of the WOM problematic. This should be a starting point to investigate other VAAs for similar patterns to reevaluate the validity of data from VAAs for the examination of party relations in general.