However, the main issue lies in the developing of a cause and effect relationship because it is difficult to assert if the observed behavior is due to the independent variable or are other variables involved (Gillian Fournier). This is an issue as the researcher has no control over confounding variables and that affects the reliability of the experiment. Another problem is that it is difficult to replicate such studies. It is difficult to do the study observation again especially if the observed behavior is rare. For example road rage, one cannot ask participants to replicate the same behavior. Also, there is a possibility of researcher bias which can affect the interpretation, evaluations and expectations.