assessing party membership figures: the mapp dataset

peer reviewedAssessments of party decline and decline of traditional forms of political participation often rely on the argument of party membership decline. Most studies analysing trends in party membership over time focus on aggregate country-level data at a few points in time. While they allow grasping general membership trends, they are not without shortcomings. This article presents the Members and Activists of Political Parties (MAPP) dataset related to the MAPP project. The dataset makes a large amount of data on party membership available to the larger public. The dataset provides 6,307 party membership data observations (M) covering 397 parties in 31 countries, mostly between 1945 and 2014. The article discusses the existing literature and data on party membership trends, how membership trends have been assessed so far, and the potential added value of the MAPP dataset