Actually, an old 1997 Cornell University study did not find a strong correlation between the GRE and ultimate grad school success.http://www.news.cornell.edu/releases/Aug97/GRE.study.ssl.html (Though, as you may suspect, other studies indicate otherwise). For professionals who have been out of the academic arena and are returning to school, they likely wouldn't score as highly as a 22-year-old recent graduate, yet they certainly have the intellect, experience and maturity to excel. It is a presumptuous, and dare I say, arrogant attitude to assume that a test score is a measurement of a person's intellect and capabilities.