A Note on Simple Gain Score Precision

A distinction is necessary between two concepts of measurement precision. Reliability is population dependent and information is examinee dependent. Both concepts also apply to the simple gain score. Low reliability implies that it is not appropriate to correlate the gain score with variables in a population, and low information implies that no precise statements can be made about an examinee’s true gain. However, low reliability does not imply that statements about within-examinee change are necessarily imprecise.