The purpose of this article is to describe the research method used by Gøsta EspingAndersen to create the three models of a welfare state, i.e., the decommodification index, as well as to show how the classification of countries within the framework of these models has changed during the last 30 years. Esping-Andersen supported his theory of three social regimes by decommodification index, however, he did not identify the results directly with belonging to a particular model. The index serves only as a tool, not a basis for building theories. By this concept, he believed that the higher and more widely distributed social security benefits are, the higher is the level of decomodification of the inhabitants of the country. The paper describes empirical (databases comparable in longer time periods), theoretical and methodological limitations of the index – method of calculating the rate of decommodification by the standard deviation and also a possible supplementation of the index by family policy measures. The result of this study is a new classification of 18 countries, originally studied by Esping-Andersen, and an analysis of why and how some of them have changed their position in the ranking. Change in the classification may be confirmed by the reforms undertaken in some countries over the years. The decommodification index in the original terms, despite its simplicity, is still useful to analyse the three models of social policy. However, a modification in terms of changes to definitions of decommodification and − important from the perspective of welfare state − social services, may be considered.