The complex phenomena of political science are typically studied using qualitative approach, potentially supported by hypothesisdriven statistical analysis of some numerical data. In this article, we present a complementary method based on data mining and specifically on the use of the self-organizing map. The idea in data mining is to explore the given data without predetermined hypotheses. As a case study, we explore the relationship between parliamentary election results and socio-economic situation in Finland between 1954 and 2003.