But obviously there are, he says, differences in his life now.
In his experience, he says, differences in scores are not consequential for students at either end of the test-taking spectrum.
Dr. Bray said differences in the taste preferences of rats and in their metabolism make it tricky to evaluate food intake, calories burned and weight changes.
Dr. Kirsten Bibbins-Domingo, of the University of California, San Francisco, and a member of the task force, said differences in the recommendations were merely a matter of degree.
A delegation from the European Union said differences in the price of ships made in Korea from those made in Europe had widened since June 2001, the last time the delegations discussed the issue.
He said differences in monitoring approaches - some areas are observed from the ground, some from the air, and some from space - are compounded by officials' fear of retribution if they report high forest fire statistics for their region.
Mizuho Ishida, the lead researcher and a former president of the Seismological Society of Japan, said differences in interpretation were inevitable because estimates had to be extrapolated from the wave data collected 12 miles offshore.
Asked why SUNY did not negotiate one jumbo group rate, David M. Henahan, the director of media relations for the SUNY system, said differences in costs between New York City and upstate New York were among the obstacles, along with other factors.
Last year, Mr Cameron said differences in NHS performance in Wales and England meant Offa's Dyke was a "line between line and death".
The charity says differences in staffing levels and equipment means UK health care trusts are failing to offer equal opportunities for patients to receive radiotherapy.
He called election officials biased and said differences in the way ballots cast for regular candidates and write-in candidates are handled are unfair.
