Children Left Behind High school graduation rates in almost every nation and ethnic group are improving. However, the United States still lags behind other nations, and ethnic differences persist, with the rate among Native Americans lowest and among Asian Americans highest. High school diplomas are only one sign of educational accomplishment: Nations at the top of this chart tend also to rank highest in preschool attendance, in middle school achievement, and in college graduation. Raising the graduation rate involves the entire educational system, not simply more rigorous or more lenient graduation standards.