For every study that shows statistically significant results, there may have been many similar tests that were inconclusive. However, significant results are more interesting to read about and are therefore more likely to get published. Not knowing how many ‘boring’ studies were filed away impacts our ability to judge the validity of the results we read about. When a company claims a certain activity had a major positive impact on growth, other companies may have tried the same thing without success, so they don’t talk about it.
The perceived feasibility of methods to reduce publication bias The 7 biggest problems facing science, according to 270 scientists Ben Goldacre TED Talk: What doctors don’t know about the drugs they prescribe