While many works have empirically studied the number of parties, little has been done to investigate the difference between theoretical predictions and empirical reality. Furthermore, the bulk of the analyses on party system development are carried out with national data, as opposed to studying electoral competition at the level where it occurs – the constituency. This article offers a comparative study of the determinants of party system convergence of twenty European democracies, explaining why party systems in new democracies are much further away from the theoretically predicted equilibrium than those in more established states. The main argument is that learning the effect of institutions is integral to understanding the number of competing parties and it takes time for political elites in new democracies to learn. Using a hierarchical model, the study shows the effect of age of democracy on party system convergence and illustrates that it is more pronounced in new democracies. The analysis demonstrates further that pre-electoral constraints such as signature and deposit requirements have a significant positive effect on party system convergence, while public funding, contrary to previous speculations, is found to be insignificant.