LAST week, Johnson & Johnson announced that it was making all of its clinical trial data available to scientists around the world. It has hired my group, Yale University Open Data Access Project, or YODA, to fully oversee the release of the data. Everything in the company’s clinical research vaults, including unpublished raw data, will be available for independent review.

This is an extraordinary donation to society, and a reversal of the industry’s traditional tendency to treat data as an asset that would lose value if exposed to public scrutiny.

Today, more than half of the clinical trials in the United States, including many sponsored by academic and governmental institutions, are not published within two years of their completion. Often they are never published at all. The unreported results, not surprisingly, are often those in which a drug failed to perform better than a placebo. As a result, evidence-based medicine is, at best, based on only some of the evidence. One of the most troubling implications is that full information on a drug’s effects may never be discovered or released.

Even when studies are published, the actual data are usually not made available. End users of research — patients, doctors and policy makers — are implicitly told by a single group of researchers to “take our word for it.” They are often forced to accept the report without the prospect of other independent scientists’ reproducing the findings — a violation of a central tenet of the scientific method.

To be fair, the decision to share data is not easy. Companies worry that their competitors will benefit, that lawyers will take advantage, that incompetent scientists will misconstrue the data and come to mistaken conclusions. Researchers feel ownership of the data and may be reluctant to have others use it. So Johnson & Johnson, as well as companies like GlaxoSmithKline and Medtronic that have made more cautious moves toward transparency, deserve much credit. The more we share data, however, the more we find that many of these problems fail to materialize. Read more.