The overall goal of the project is to develop theoretical models for how the selection of politicians works in proportional electoral systems. These models will then be tested empirically on unique Swedish data. The selection of politicians takes place to the ballot, to the higher seats on the ballot, and to the more influential positions in the political hierarchy. We will answer five main questions regarding how this process works, namely how the selection is affected by 1) formal institutions in the proportional electoral system, 2) external factors such as competition between political parties and media coverage, 3) the characteristics of party leaders and 4) private networks between politicians. In addition, we will analyze how the policies implemented are affected by the end product of selection, i.e. the socio-economic composition of the elected representatives. Today, there is a lack of both useful theoretical models and empirical studies on these issues. Our scientific contributions come from both the theoretical and empirical side. The research group has unique expertise in developing theoretical models through the participation of two of the world's leading researchers in political economy, people who have participated in the development of several of the most widely used models in the field today. On the empirical side, important contributions will be made using the most detailed data set of elected and non-elected politicians ever assembled.