Granting citizenship to non-natives is obviously a very heated and controversial topic across many European countries. What we were interested in is answering this question empirically. What is the impact of giving the host country passport to immigrants? It’s actually not an easy question to answer empirically and that’s because naturalised immigrants are very different from non-naturalised immigrants. Naturalised immigrants typically have more resources, are more motivated, and are probably already better integrated at the time of applying for the host country citizenship. Ideally you’d like to do is that you do a large field experiment where are you randomly hand out to host country passport to some immigrants but randomly withhold it from others and then after two or three years you collect the outcomes and see if the naturalised immigrants are better integrated than the non-naturalised ones. I suggested that this research designed to the Swiss Ministry of migration and they laughed at me and I had to look for something else. Fortunately there was a very particular institution in Switzerland that allows us to answer that question. Namely, in some municipalities all the voters vote on each individual citizenship application. If you receive 50 percent or more of the “yes” votes you receive with citizenship and if you receive 49 or less percent, you don’t. And so we use that to compare people who barely have received citizenship, say, with 51 percent to people who were barely rejected, say, with 49 percent. This decision to receive the Swiss passport is essentially as good as random. These immigrants are not different in terms of their background, in terms of their previous integration – that allows us to estimate the causal effect of citizenship on long term political and social integration. And so the big finding is that these people who were very similar back in 2003, at the time when they applied for for citizenship, 15 years later the naturalised immigrant is much better integrated both politically and socially in the host country. Their political knowledge is about the same as with rooted Swiss natives. They are more likely to have plans to stay in Switzerland, are less likely to feel discriminated against. They read Swiss and not just for news papers and also feel like they have a say in the political process. While the rejected applicant is still marginalised both socially and politically. There are two things that were surprising to us. On the one hand it was the size, the magnitude of these effects which is really huge. And the second thing what we found is that the benefits of naturalisation. Are largest for the more marginalised groups of immigrants and this is not something that we expected.