Monday, September 20, 2010

Accuracy Versus Validity

FLG heard an interview with an author not too long ago, and he made a point about accuracy versus validity. To oversimplify -- there's a fundamental tension between making a test repeatable, objective, and accurate versus it testing what we want it to.

The author provided IQ tests as a prime example. They are repeatable, objective, and accurate in that your IQ doesn't change all that much over your lifetime. However, it's not a particularly useful predictor of your future.

To make a valid test it often needs to be subjectively graded and less repeatable. FLG couldn't help but think of that interview when he read this article with recommendations for changing standardized testing in schools.

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