Question

When would you use an observational study instead of experimental approach?

Answer 1

n the fields of social science, psychology, epidemiology, medicine and others, observational study is an essential tool.

In classical scientific experiments, the researcher finds a way to manipulate the independent variablesto see the effect this has on the dependent variables. However, manipulating the independent variable is sometimes impractical or outright unethical.

 For example, a neuroscientist may be interested in the outcomes of patients with a rare kind of brain damage. But it will never be feasible to deliberately cause that kind of brain damage (the independent variable here) in an experimental group to measure patient outcomes (the dependent variable).

Thus, observational methods (sometimes called “un-manipulated studies”) entail merely observing phenomena that are already underway. For a study of long-term effects of brain damage, for example, researchers have to use patients with pre-existing brain damage or their medical records. An observational study can then make inferences from that small sample to the general population, helping neuroscientists understand any new instances of that kind of brain damage.