Badanie zależności pomiędzy systemem wyborczym a systemem partyjnym przy wykorzystaniu metody indeksowej. Przypadek mieszanych systemów wyborczych w Rosji i na Ukrainie oraz proporcjonalnej reprezentacji w Polsce

The article describes the most common indicators (so-called indices) and the methods of combining as well as interpreting them in the political science comparative studies. An employment of these indices allows the analysis of the impact of electoral systems on party ones. Using Russian and Ukrainian mixed electoral systems and Polish proportional representation as an example, the author expounds the impact of given elements of electoral systems on configuration of party systems. Proceeding so, he gauges the effects of the influence in question by deploying the so-called effective number of parties formula. The author points out that amongst others effects of this interconnection of systems there is also the impact on the concentration level of party systems. Additionally, this paper debunks a plethora of popular opinions concerning political effects of electoral systems and teaches how one can verify those opinions employing the index method and how to interpret the indices.