areas with high unemployment as well as a higher share of right-wing voters.

These results hold several important lessons for policy. First, the German case shows that a large and sudden increase in the number of asylum seekers had only small effects on many dimensions of social cohesion – at least in the short run. Our results counter an often-expressed fear – and common argument against hosting refugees – that immigration undermines the foundations of societies in the host countries. This insight, in turn, holds lessons for the design of refugee policies. A fairer distribution of refugees across countries would require rich countries to host more refugees. Our results suggests that this can be done without major impacts on social cohesion.

A second lesson is about the differential regional impact of refugee inflows. In some regions – predominantly those with a strong regional economy and voters that are open to the idea of hosting refugees – the effect on anti-immigrant violence is non-existent. In other areas – often those with high unemployment and a large share of right-wing votes – we see a strong effect on anti-immigrant violence. This information can be useful for the design of assignment and integration policies. It is imperative to adopt policies that foster inclusiveness and empathy with immigrants, and to target areas that are prone to anti-immigrant violence.

A third lesson is about defining and measuring social cohesion. Social cohesion is an important characteristic of a thriving society, but it is neither straightforward to measure nor to define. Our results highlight the importance of considering multiple data sources as well as multiple dimensions of social cohesion in order to get a nuanced picture of the consequences of refugee inflows. If we only relied on survey data, we would conclude that the local presence had no effect on social cohesion. However, when we look at anti-immigrant violence – an extreme expression of undermined social cohesion – we see effects that should be a concern for policymakers.

# **2 Migration to Germany: Historical Context**

Our goal is to document the social effects of the immigration wave in 2015/16, when approximately one million refugees and asylum seekers from countries such as Syria, Afghanistan, Iraq and several countries in the West Balkans arrived in Germany. Although this immigration wave posed significant challenges to the country, its scale was not unprecedented. Since World War II, Germany has been the destination of millions of immigrants. The first – and to date largest – migration wave was the arrival of 12 million Germans between 1944 and 1948, who were expelled from German territories that were ceded to Poland and the Soviet Union (Pomerania, Silesia, East Prussia) as well as from countries in Central and Eastern European such as Czechoslovakia, Romania or Serbia (e.g. Kossert, 2009). Another 4.5 million ethnic Germans moved to Germany from Eastern Europe between 1988 and 1998 (Worbs et al., 2013).

Between the division of Germany in 1949 and the fall of the Berlin Wall in 1989, both parts of Germany had separate migration regimes and, consequently, Germans who grew up in either part had different experiences with migration. East Germany severely restricted the emigration of its own citizens. After the building of the Berlin Wall in 1961, it was nearly impossible to legally leave the country; until 1988 around 600,000 people moved from East to West Germany, most of them illegally (Bade and Oltmer, 2004). In the 1950s and 1960s, both parts of Germany introduced guest worker 2