As with any type of test or evaluation whose results will be applied to takers based on accepted standards, a clinical assessment should only be selected if its sampling method was sound.
At the simplest level, according to Dr. Shirag Shemmassian, Ph.D. in his article “How to Select the Assessments You Use with the Population You Serve”, a proper sampling method means that a given assessment has been administered to enough individuals in the population it’s designed to serve.
However, it’s essential to understand that while sampling sounds simple on the surface there are actually many factors that must be considered before concluding that an assessment’s standardized sample is actually representative of the population it claims to represent. Some of the most significant factors are:
- Socioeconomic Status (SES)
Bearing that in mind, it is known that publishers attempt to ensure that their assessments standardized sample is a nationally representative sample with “roughly the same percentage of individuals from various groups as those groups are represented in the population” based on the five factors listed above.
Once an assessment is administered to a sample of a population they believe fairly represents the overall group scores from the assessment are collected and studied to prove that there are no meaningful or significant differences in the results where none were expected. Or in other words that the sample of a given population behaved in the way that was expected based on the assessment’s results. If there were significant difference between certain groups within the samples (say urban versus suburban raters) different norms may be created to let clinicians know that these differences are expected.
Although, we must note that when working with a sample to verify an assessment it’s still not possible to capture the entire range of human diversity that may lead to different or skewed results when administered by different clinicians. This is because even within a certain population, such as college educated African Americans, there will still be a range of experiences, abilities, habits, etc. that influence the test beyond the factors publishers anticipate.
That being said it’s important to understand that trusted publishers have created assessments for use by clinicians that are a close enough representation of a population to ensure useful results for recipients of their professional care and guidance. The easiest and most effective way to search for assessments that have been vetted with a proper sampling method is through a reliable source for clinical assessments, such as Western Psychological Services, which provide detailed descriptions of their assessments, including the sampling pool the scores are based on.
With knowledge of the sample an assessment was tested against to determine if it could represent a given population a clinician will know that they are selecting a resource that will serve their patients well and provide them with results that they can use to guide future treatment.