Epidemiology regularly encounters this problem because you can't experiment on humans(you can't hurt them) Epidemiology relies on mountains of data to test a hy

Epidemiology regularly encounters this problem because you can't experiment on humans(you can't hurt them) Epidemiology relies on mountains of data to test a hypothesis. The problem is when you are asking the data to tell you about something exceedingly rare. For example say you think a rare brain cancer is caused by high levels of exposure to gamma radiation plus a genetic predisposition. Because genetic testing is relatively new, and exposures to gamma radiation at high levels are rare. You might come up with so much noise in your data that all results are meaningless. This is one reason there is very little progress made on rare diseases and conditions. Of course the same problem occurs when something is extremely common.