The American Medical Association wants more transparency in clinical trials, a proposal that may leave drug companies and investors with mixed feelings.

Little matters more in the pharmaceutical world than clinical studies, so, understandably, anyone who follows the industry obsesses about them. Unfortunately, it's not always easy to track down facts. Not long ago, I ran a project that sought to uncover the latest data available on all drugs in development. While there are a number of places to turn, from free outlets such as ClinicalTrials.gov and corporate websites to pricey subscription services, even the best sources can contain out-of-date, fragmentary, and confusing information.

So, a national database would seem to be a positive step. But, of course, there are two sides to every story. Motley Fool Income Investor recommendation Merck (NYSE:MRK) made news late last week by supporting such a repository, or clinical trials registry, but only for late-phase and post-approval investigations. GlaxoSmithKline (NYSE:GSK), which is in hot water over alleged impropriety related to Paxil, plans to launch its own online registry, providing access to studies of approved medicines. It seems, then, that drug companies are willing to be more open, but only with respect to advanced or marketed medicines.

There are good reasons for their caution. Widely available data on early studies might sate the gaping maw of the investing public, but companies presenting the information could hurt themselves competitively. Copycats would have an easier time latching onto rivals' ideas and catching up. An open database could be particularly damaging to smaller players, which, due to limited resources, often concentrate on a lead candidate, while leaving other potentially promising treatments lingering for years in early studies. In this scenario, biotech companies would face the danger of forfeiting novel but unproven concepts to well-heeled competitors.

In addition, the findings of early studies can be misleading. Since they are smaller and shorter term, phase 1 and phase 2 trials may or may not be accurate indicators of a medicine's effect on a larger population. Furthermore, interpreting results can be a challenging task, even for experts.

Purists may argue that more openness is always a good idea. But in this case, releasing more of this data may increase, rather than relieve, confusion.

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Fool contributor Brian Gorman is a freelance writer living in Chicago, Ill. He does not own shares of any companies mentioned here.