Multilevel approaches to panel data – an application to human rights violations in established democracies
Panel data - i.e. the observation of multiple variables over multiple time intervals for the same units of analysis - often suffer from various violations of the Gauss-Markov assumptions. For example, in many settings it can hardly be assumed that repeated measurements within units are independent of each other. In contrast to seminal pooled time-series models, multilevel approaches can directly model such dependencies by allowing for varying intercepts and slopes. This enables us to disentangle temporal from cross-sectional variation and to study their cross-level interactions.
Dag Tanneberg exploits such models to study violations of physical integrity in established democracies, distinguishing variation due to political threats over time from cross-sectional variation due to the institutional context of individual democracies.