Ecological validity is a type of external validity which looks at the testing environment and determines how much it influences behavior.
In the school test example, if the pupils are used to regular testing, then the ecological validity is high because the testing process is unlikely to affect behavior.
On the other hand, taking each child out of class and testing them individually, in an isolated room, will dramatically lower ecological validity. The child may be nervous, ill at ease and is unlikely to perform in the same way as they would in a classroom.
Generalization becomes difficult, as the experiment does not resemble the real world situation.
Oskar Blakstad (Mar 19, 2009). Ecological Validity. Retrieved Oct 02, 2023 from Assisted Self-Help: https://staging.explorable.com/en/ecological-validity