Causal analysis of Covid-19 Spread in Germany

In this work, we study the causal relations among German regions in terms of the spread of Covid-19 since the beginning of the pandemic, taking into account the restriction policies that were applied by the different federal states. We propose and prove a new theorem for a causal feature selection method for time series data, robust to latent confounders, which we subsequently apply on Covid-19 case numbers. We present findings about the spread of the virus in Germany and the causal impact of restriction measures, discussing the role of various policies in containing the spread. Since our results are based on rather limited target time series (only the numbers of reported cases), care should be exercised in interpreting them. However, it is encouraging that already such limited data seems to contain causal signals. This suggests that as more data becomes available, our causal approach may contribute towards meaningful causal analysis of political interventions on the development of Covid-19, and thus also towards the development of rational and data-driven methodologies for choosing interventions. 1 Although SyPI's conditions are necessary only for single-lag dependencies, the method has provided satisfying results even with multiple lags [6] . The existence of multiple lags would only result in fewer detected causes, without affecting the validity of the method in terms of false positives. 2 ' ' denotes a directed path, '--' denotes a collider-free path.