A standardization sample is a population of individuals who have previously well-documented intelligence and/or achievement levels that are used to “standardize” new or revised test instruments to assure that they are reliably measuring what they are intended to measure.
For instance, standardized tests such as the WISC-R or the WAIS-R are periodically updated to reflect changes in society and education norms. These new revisions of the test are then given to a large sample populations to make certain that they are accurately measuring the intended skills and knowledge.