You're reading a magazine and find an article entitled "Study Shows Drinking Coffee Is Good for Your Health." Later, mug of coffee in hand, you are reading a news website and happen upon this article: "Study Shows Drinking Coffee Is Dangerous to Your Health." You pour your coffee into the sink and wonder which article is true.
Is there a way to figure out which of these studies is right?
The best method to decide on the value of a study is to check it against the Hierarchy of Evidence, a tool that ranks the strength of a study's evidence based on the way the study was designed.
The types of evidence listed below are ranked from weakest to strongest. Keep in mind that sometimes a study may not be able to provide certain types of evidence for various reasons, including legal and/or ethical ones.