Types of validity in the search: predictive validity
We know psychology uses tests to make inferences about people, but what are the scores in these tests?This is responsible for the validity. As explained in another article, there is not only one type of validity, but several, in this article we explain the role of predictive validity.
- Researcher Robert Thorndike (1989) explains that the validity of a test is related to what you are trying to measure.
- So from this premise one may ask: is the use or interpretation of the scores of this test appropriate?Can generalizations be made without introducing a very wide margin of error of the test results?Validity covers all these issues.
In statistical terms, validity is defined as the proportion of true variance that is relevant to the purposes of the test. But what does the relevant term mean? In this case, it refers to the characteristics, or dimensions, that the test used is capable of measuring.
As mentioned earlier, the validity of a test is defined
As mentioned earlier, there are several types of validity, specifically, the validity types are:
Do test results predict future performance or behavior?(1) The function of external validity is to answer this question.
In psychology, tests are commonly used to predict future behaviors, so we use the test to help us make practical decisions (classification, selection, etc. ). In each of these situations, the higher the accuracy of the prediction, the greater the predictive validity of the test and therefore the more useful it will be. (1)
For example, let’s say we use a test in a hiring case, in this case the test will be an acceptable component of the hiring process as long as its scores allow for a significant component of the work provided by the interviewees. called external criterion.
Thus, researcher Jaime Aliaga says that for the test to be used as part of a necessary recruitment process, as you can imagine, it must be valid, in this sense the idea is to link the test to the relevant criteria. It is understood that the fundamental interest of the psychologist or evaluator is to determine whether the applied test provides for a certain criterion.
To achieve this, says researcher Aliaga, we need the external criteria with which the test results will be linked to be reliable and valid criteria, but what are the criteria?
According to Aliaga, one criterion is any action of people in real life. For example, a criterion could be a measure of job performance or a measure of academic performance for a student. We could talk about many other types of these criteria. But the problem, Aliaga says, is that in many cases it is impossible to find an unequivocal criterion for a mental trait.
Let’s say, for example, that two psychologists jointly investigate the academic performance of several students, so, researching the same thing, the two psychologists can use different criteria, for example, the first psychologist might consider test scores as a criterion. Second, the correct criterion could be considered to be the time it takes each student to complete each task.
When we want to validate a test, its predictive validity (as well as its competitive validity) is usually expressed by a correlation coefficient between the scores we call criterion, this coefficient is called the validation coefficient. According to Aliaga, the interpretation of this coefficient requires an excellent mastery of the statistical analysis used to obtain, after obtaining it, the next important step to obtain the category of validity are the statistical procedures used.
To determine the validity of a test requires predictive validity, logically, and more precisely in the field of psychology, a test is better the more valid it is, in addition we must take into account that the key aspect of this type of validity is the test, so we need tests that serve as reliable and valid criteria, thus we will be able to correctly determine predictive validity.