This paper advances the study of democratic trajectories – whether democracies deepen, stagnate, erode or break down over time. We show that econometric panel models usually neglect cumulative effects, which are implicitly central to many theories of democratic change. Some important factors, such as economic growth, have cumulative effects that shape medium- to long-term regime trajectories. To overcome the limitations of conventional statistical estimators, we propose the use of latent growth curve models, which are better able to capture cumulative processes. We demonstrate the advantages of this approach by analyzing the trajectory of 103 democratic regimes inaugurated after 1974. Conventional estimators fail to predict democratic trajectories, while latent growth curve models properly capture cumulative effects.