Evidence to Correct Misperceptions About Rorschach Norms

Determining why normative values for a test may change is not easy. For instance, intelligence test scores have been changing at a dramatic rate, though the cause remains unclear (Flynn, 1999; Raven, 2000). Each time an IQ test is renormed, the same level of cognitive capacity is associated with a lower score. The ability that would have produced an IQ of 100 two generations ago would now only produce an IQ between 82 and 64, depending on the test. Thus, the average person from two generations ago would now look 1.2 to 2.4 standard deviations (SDs) more impaired (i.e., Cohen’s d of –1.2 to –2.4). Stated more dramatically, the day an IQ test is renormed, it begins “to label thousands of children as mentally retarded