If the scientific studies are registered before being performed, the researchers cannot hide the bad results by not publishing the article. As a consequence, there are much less successes.
“The researchers looked at 30 large National Heart Lung, and Blood Institute (NHLBI) funded trials between 1970 and 2000. Of those studies, 17 or 57% showed a significant positive result. They then compared that to 25 similar studies published between 2000 and 2012. Of those, only 2 or 8% were positive. That is a significant drop – from 57% to 8% positive studies.”
▻http://theness.com/neurologicablog/index.php/registering-studies-reduces-positive-outcomes