Hello, My question is probably geared towards the professors or postdocs reading this forum and concerns the recruitment aspect of the professors in the US. I am a European physics student currently visiting a "top" Californian university. During this short visit (8 months) I have come to realize that almost all the professors in the Area hold a PhD from a very narrow selection of top US university (I counted somewhere around 10 universities at most). And in the whole department few professors have done their PhD in Europe. In addition, very few of them are non-US citizens (although they might have acquired the US citizenship after such a long stay in the US). This is very intriguing for me as my home university in Europe has around 70% of foreign professors, and very few of them hold a PhD from the said university. I understand getting a tenure track position in the US is like getting drafted in the NBA and that one must be an excellent individual to reach such a position. However I was wondering how do the US universities recruit their professors. I know better universities tend to produce better professors, but this huge disparity is difficult to understand just in term of quality. Is there a cutoff selection based on where you do your PhD and citizenship or was this just chance ? For example, the postdoc seems to have less of an impact as the PhD in this matter. As a European citizen starting a Phd back in Europe this is a matter which interests me a lot. This could also be interesting for a US citizen doing a PhD in a "lower-ranked" university. Best.