Ecological validity


 * For the ecological validity of a cue in perception, see ecological validity (perception).

Ecological validity is a form of validity in an experiment. In order for an experiment to possess ecological validity, the methods, materials and setting of the experiment must approximate the real-life situation that is under study. Unlike internal and external validity, ecological validity is not necessary to the overall validity of an experiment.

External vs. ecological validity
Ecological validity is often confused with external validity (which deals with the ability of a study's results to generalize). While these forms of validity are closely related, they are independent--a study may possess external validity but not ecological validity, and vice-versa. For example, mock-jury research is designed to study how people might act if they were jurors during a trial, but many mock-jury studies simply provide written transcripts or summaries of trials, and do so in classroom or office settings. Such experiments do not approximate the actual look, feel and procedure of a real courtroom trial, and therefore lack ecological validity. However, the more important concern is that of external validity--if the results from such mock-jury studies generalize to real trials, then the research is valid as a whole, despite its ecological shortcomings. Nonetheless, improving the ecological validity of an experiment typically improves the external validity as well.