Observational Studies - An observational study is the studying of individuals who happen to meet the criteria of the question being raised. However, the subjects are not influenced by the study or researchers. The subjects just go about their daily lives, performing their daily habits, its usually these habits that are being observed, and then after some time the researchers are able to see any changes that took place in the individual. An observational study has minimal to no interference from the researchers. An example of an observational study is to collect a group of people who all have something in common. An example would be to find 30 men who all went bald before they were 30. Next is to ask them all about their daily lives, habits, diets, where they live, and many other questions that may indicate where they live that may indicate a connecting source to their premature balding. The researchers will most likely have a theory in their head that they will be looking to see was the cause.
Lurking Variable- A lurking variable is a that may have influenced the result of the study rather than the variable being tested. For example: The men are all carriers for male -pattern baldness and it is not actually something they have been exposed to or been doing in their lives causing the balding. A lurking variable causes confounding because the researchers may find a common pattern within the lives of the men that lead them to believe this variable is the cause of baldness and they will publish their findings. However, in reality it is a pre-existing hair loss condition and the researchers are accidentally publishing inaccurate statements.