Most Medical Studies Are Wrong

I've always had the feeling that the medical studies that create such a stir in the media do so because they defy common sense(""Does pot actually make you smarter?" "Does tap water make you autistic?"), and is therefore titillating.  But I was shocked when this article stated that:

In a survey of the recent literature... 95 percent of the results of observational studies on human health had failed replication when tested using a rigorous, double blind trial.

In other words, don't believe every study you read in USA Today.   It can take years for a study to become accepted as settled science.  Believeing something because some grad students got some interesting results, and then repeating the meme to all your friends, is at best wishful thinking, and at worst poisoning the well of conventional wisdom.  Have some patience, wait to see if the results can be replicated, and don't bother adopting beliefs without good reason.