Psychometric considerations in functional status instruments

Abstract

Psychometrics is simply about measurment. Good measures of the variables being studied are essential to assure that the question of interest can be answered. The adequacy of measures can be judged in terms of their variability, reliability, validity (including response bias), sensitivity, practicality, and interpretability.* These features of good measures will be described here as they apply to measures of functional status in clinical settings. The advantages of multiitem measures over single-item measures are reviewed, and a few suggestions are made regarding the evaluation of the clinical utility of the measures.