But randomized controlled clinical trials also are used to prove benefit in big drug studies.

FORBES

Cannon says only to weigh data from controlled clinical trials, which are expensive and are funded mostly from drug companies.

FORBES: In Vioxx's Wake

In June, the British Medical Journal published a major analysis of all the controlled clinical trials that have so far been presented.

FORBES: Magazine Article

When big, controlled clinical trials designed to compare two medicines emerge, the results often resemble what Graham managed with a supposedly less-sensitive study.

FORBES: Face Of The Year: David Graham

Estrogen hormone replacement therapy seemed to have all sorts of benefits based on observational studies, but they vanished under the more rigorous lens of controlled clinical trials.

FORBES: Can Cholesterol Drugs Prevent Cancer?

From the time a hint of heart risk first showed up in a clinical trial designed to prove Vioxx was safe for the stomach, Merck has had one response to many of its critics: It would consider data only from controlled clinical trials.

FORBES: Grading Merck's Defense