I discuss the unfortunate bias against publishing "negative" scientific results that show a drug doesn't have much clinical benefit, and why it's in the self-interest of drug companies to still report these.
In particular, I highlighted two interesting facts:
1) Most drug trial results are still not being reported to a central registry.Fortunately, free market incentives are driving more drug companies towards full disclosure of both positive and negative study results -- which will benefit patients.
2) Negative results funded by private industry (e.g., pharmaceutical companies) are more likely to be reported than from government-funded research.
For more details, read the full text of "The Positive Value of Negative Drug Trials".
("Fluoxetine 20 mg capsules" by Tom Varco - Own work. Licensed under CC BY-SA 3.0 via Commons; source: Wikipedia.)