Ben Goldacre in this TED talk video alerts us to the fact that "negative" studies are rarely published, and the real world implications. Publication bias is "the technical term...where unflattering data gets lost...unpublished...missing in action." Very enlightening. "If I flipped a coin a hundred times but then witheld the results from you from half of those tosses, I could make it look as if I had a coin that always came up heads. But that wouldn't mean I had a two headed coin, that would mean that I was a chancer and you were an idiot for letting me get away with it. But this is exactly what we blindly tolerate in the whole of evidence-based medicine...the effect on patients is damning."