Monday, December 03, 2007

The inherent unreliability of psychological tests - Misdiagnosis likely

A recent study raises serious questions about the validity of current psychological testing methods, and demonstrates how much is not known. The author offers several possible explanations for the results, which are basically filler substituting for a generic "I don't know what is going on" answer.

This has profound implications for many other psychiatric and psychological diagnostic "tests", such as for ADHD, etc., which involve questionable diseases to begin with.

Left unsaid is the profound danger of misdiagnosis, horrific because of the toxic side effects of many psychiatric medications prevalent on the market.

From Science Daily.

The study is published in the July issue of Neuropsychology, which is published by the American Psychological Association (APA).

Salthouse gave 16 common cognitive and neuropsychological tests to evenly divided participants (90 in the first, 1600 in the second) into groups of ages 18-39, 50-59 and 60-97 years old. In both studies, the variation between someone's scores on the same test given three times over two weeks was as big as the variation between the scores of people in different age groups. It's as if on the same test, someone acted like a 20-year-old on a Monday, a 45-year-old the following Friday, and a 32-year-old the following Wednesday. This major inconsistency raises questions about the worth of single, one-time test scores.

"I don't think many people would have expected that the variability would be this large, and apparent in a wide variety of cognitive tests -- not simply tests of speed or alertness," says Salthouse.

[...]


American Psychological Association (2007, July 3). Cognitive Scores Vary As Much Within Test Takers As Between Age Groups Making Testing Less Valid. ScienceDaily. Retrieved December 3, 2007, from http://www.sciencedaily.com­ /releases/2007/07/070702084329.htm

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