Using the correct standardization group is very important! The researchers select what is called a "stratified" random sample from several locations: urban, rural, metropolitan, etc. Researchers make sure that a certain number of examinees are from each subgroup. Their raw scores are then averaged to create the norm of the test. I have seen a few tests use completely different norms between countries and report those norms in the same test manual. I have never felt that those norms were reliable.
What other threats to the validity of tests could there be?
An important threat to the validity of tests is not testing the research subjects or sample under the same conditions. This is due to the fact that testing one group under ...
This solution describes threats to psychological test validity.