The illusion of validity is cognitive bias that occurs when an individual overestimates their ability to predict an outcome when analyzing a set of data – especially when the data appears to have a consistent pattern or appears to ‘tell a story.’
For example, this can occur when someone like a teacher or social worker looks at a client history and believes that they know for certain how a case is going to play out in the long run or how well a student will do in a course. However, people are resourceful or events can take unexpected twists and turns; the end may turn out totally different than predicted.
As an example, a teacher looks at a student’s stellar behavioral record and previous good grades and predict they will have no issues with the student and they will easily get an A in the class. What the teacher doesn’t know is the child’s parents are divorcing and having a rough time – this may cause the student to have behavioral problems and their grades to slip. The illusion of validity caused the teacher to make a prediction that in the end did not come true.