for services. Younger members undergo some costly personal sacrifice in the case of the Taliban and Hamas (we know less about initiation of Hezbollah fighters). All three groups changed their ideologies drastically: Hamas in choosing armed conflict, the Taliban in deciding to protect Bin Laden and Hezbollah in shifting from a rebellion against Israeli occupation to an ethnic militia/political party after Israel's withdrawal from South Lebanon in 2000. There are differences: Hamas view most Palestinians as potential members, as Hezbollah regard Lebanese Shia, while the Taliban treated most Afghans as a conquered people. Yet the common elements, and especially the common puzzles, seem to justify analysis in parallel. Berman argued that such parallels were common to other radical religious groups. On Ultra-orthodox religious groups Berman has also done field work among ultra-orthodox religious groups in Israel. Studying full-time Yeshiva students, who Berman finds study until 40 years old on average, and whose families have 7.6 children per woman (in the mid 1990s), he concludes that "Subsidies induce dramatic reductions in labor supply and unparalleled increases in fertility." In a 2000 NBER paper, Berman describes Ultra-Orthodox Jews as "a fascinating and fast-growing sect which has held virtual veto power over [Israeli] public policy for more than two decades." On the relationship between unemployment and insurgency Berman's NBER paper Do Working Men Rebel?, co-authored with Joseph Felter and Jacob N. Shapiro, drew the counterintuitive conclusion that reducing unemployment does not reduce insurgency-related violence. In an interview, Berman explains the findings as "insurgencies are very small organizations which need very few fighters to keep them going, and are often not constrained by a lack of recruits—and even if they were there's nothing to stop young men from working by day and planting roadside bombs by night." Personal life Berman was born in Ottawa, Ontario, Canada. He describes his parents as "middle-of-the-road North American Jews." In 1981, Berman became an Israeli citizen, saying that he had "thought the Jewish experience would be more interesting in Israel". He then participated in the 1982 Lebanon War. Berman is now a US citizen. He is married and has two children. Education and academic career After leaving the Israeli Defense Forces in 1985, Berman studied at the Hebrew University of Jerusalem. He graduated with bachelor's degree in computer science and economics in 1987, and in 1989 obtained a master's in economics from the same university. He then obtained