BTW, not sure if you're still following this thread, but here's some info on attrition: www.cgsnet.org/portals/0/pdf/N_pr_PhDC_bookII.pdf Looks like there is

BTW, not sure if you're still following this thread, but here's some info on attrition: www.cgsnet.org/portals/0/pdf/N_pr_PhDC_bookII.pdf Looks like there is a statistically relevant difference in completion rates - international students tend to complete at 67% vs 54% for US citizens - and that this gap is driven by math and physical science, while humanities only has a 2% gap. So while I wouldn't say there is a vast gap, there is a relevant gap. While 67% is much preferable 54%, keep in mind that at elite law, med, and business schools, completion rates tend to be in the high 90s.