Debates on the impact of jurisdiction size on local democracy have a very long tradition, but in spite of numerous empirical studies, the results are still far from conclusive. Methodologically rigid studies of the relationship based on data from Poland or other countries of Central and Eastern Europe have been so far very rare. Moreover, earlier studies focused predominantly on the amalgamation reforms and it is assumed that the effects of fragmentation simply “mirror” the observed effects of territorial mergers. The paper tries to answer empirically that question and aims at filling the gap in the existing studies. We apply a quasi-experimental research scheme, based on matching and difference-in-differences method, in order to analyse 13 out of 15 cases of municipal splits which occurred in Poland between 1995 and 2010 (two cases have been excluded due to changes in the electoral system being result of the split, which might interfere with the effects of fragmentation). We seek the influence of territorial reform on electoral participation and competitiveness (measured by the supply of candidates and average seat marginality). While the treated units are municipalities, in order to better understand the interplay between size, competitiveness and turnout, we conduct the analyses at the electoral district level.
