The study is "the most rigorously conducted to date," Dr. Buse said, and its authors are "exceptionally well known in the diabetes and medical world."

But Dr. William Gradishar of Northwestern University, the lead investigator in the clinical trial, said it was conducted rigorously.

But more recent, and more rigorously conducted, research has revealed that MIT can be very effective at recovering language function.

When individual lives are at stake, the tests must be conducted more rigorously than those now performed for statistical purposes.

But two investigations by committees appointed by the university found that the study was rigorously conducted in a way that complied fully with the contract.

There are also rigorously conducted, silent retreats during which not a single word is uttered by guests or staff, not even to say goodbye.

Handling of such sensitive cases by the Justice Department, however, would come at a high price - less public confidence that investigations of top Government officials were being conducted rigorously and impartially.

Moreover, if conducted rigorously, all these different approaches should be consistent with each other and lead to the same investment decisions.

Dr. Allan said one federally financed study, the Women's Health Initiative, was particularly important to the task force because it was a large and rigorously conducted clinical trial.

Only the most rigorously conducted research can produce results which are truly meaningful.