Rebecca
I agree about the importance of understanding immigration policy effects on health. Several people in the class have related concerns so we should have enough brainpower as a class to design something that will give us insight. Is there any regional variation in how PEP is implemented or arbitrary institutional features that could be used as natural experiments. Because you posit spillover effects, would effects potentially spill over to people who are not directly threatened? If so, you might be able to use temporal changes in the well being of legal immigrants with strong social ties to undocumented immigrants to develop an argument about the health effect of enforcement policies.
maria