Question

Discuss an example each of a threat to external validity and internal validity.

Answer 1

Internal Validity means how well the the experiment is measuring what it is supposed to measure and how well it is avoiding confounds. Example - In a Quasi experimental study of comparison of Intelligence between drinkers and non drinkers, it poses a threat to Internal Validity as there is no random assignment and the groups are different.

External Validity is the extant to which the results of the study can be generalized to other situations or people. For Example - Research on a drug has shown to have anxiety reducing properties in a sample of patients with schizophrenia. These results cannot be applied to normal population as the sample is not normal population.