Saturday, January 1, 2011

Dr. Doug Detterman's bytes: Psychometric reliability

Another of Dr. Doug Detterman's intelligence bytes.

Reliability is consistency. A measure is reliable if it provides the same measurement on repeated applications. A measurement is an attempt to estimate the value of a true score or latent trait. If it were possible to measure this true score or latent trait value exactly, the measurement would provide the same value on each measurement occasion so long as the trait remains unchanged. However, measurement is never perfect. There will always be some error. To understand the accuracy of any measure requires knowing the amount of error in the measurement.

One of the reasons so many important relationships have been found with intelligence is that they are highly reliable.

All good science begins with reliable measurement. As Pavlov put it, control
your conditions, and you will see order. This is why reliability is so important and
probably deserves even more attention than it was given here

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