[psycr]

Depends on the effect size.

You probably only need n = 5 for a confident answer to the question "What happens when you are shot in the head?"

[fullshark]

Studies of the form article mentioned helped solidify the link between smoking and cancer also.

People are looking for smaller effects than before, and the incentive to publish any and all significant results is just so great that you get tons of noise.

[Aelinsaar]

Maybe, but even then you have the Gabrielle Giffords, Malala Yousefzais, not to mention Phinneas Gages of the world.