Widać zabory? Analiza zróżnicowania przestrzennego nieważnych głosów w wyborach centralnych w Polsce w latach 2004–2019

The percentage of invalid votes in national elections in Poland, has not been studied as extensively as in the case of local elections. There are many research gaps in this area, starting with the description of the spatial patterns of this diverse phenomenon. This article has this main goal: to describe the spatial patterns of the percentage of invalid votes in the elections to the Sejm, the European Parliament and the President of the Republic of Poland in the years 2004–2019. The key of this study is a long-term analysis of the above-mentioned problem, as well as a look at the changes taking place in space-temporal terms. For this purpose, the methods of comparative map analysis, spatial classification and statistical analysis: Kruskal-Wallis and Student’s t-tests were used. The most important conclusion from this work is the universality of spatial patterns of the percentage of invalid votes in the case of elections to the Sejm and the European Parliament and some differences in the case of presidential elections. The persistence of interregional differences is also noticeable, but we can observe strengthening of these differences in the case of parliamentary and presidential elections, and weakening in the case of elections to the European Parliament. The article also presents an explanation for the significant increase of invalid votes in the Bydgoszcz district in the 2005 Sejm elections, which was caused by the unusual design of the brochure ballot card.