[Guenevere]

Where does common sense factor in?

Adolescent sexual experimentation and drugs .....

... doesn't take a rocket scientist....

...or multiple 'studies'....

.. to know it can cause depression!

[Old Student]

"Where does common sense factor in?"

You had perhaps not noticed that common sense is not very common anymore. Researchers are, among other things, trying to find out if common sense is actually right. Sometimes it is, sometimes not, apparently.

As far as why more studies are needed, the whole purpose of research is to find out what is true and applicable to the most people possible (speaking of research on people,that is). The more people they've researched, the more likely they are to approximate the truth, because that makes them more likely to have gotten a look at all the variations possible.

Look at the research on heart attacks. For decades they've generalized on about both men and women based on studies on men. They have only recently begun to notice that women don't usually have heart attacks with the same symptoms men do. They are also finding that things that work for helping men who've had heart attacks may not work as well on women, either. Need more research to find out what's up with that, too.

There are some folks who take advantage of the situation, though. Lots of unnecessary research goes on.