How we should measure "change": Or should we?

Abstract

Procedures previously recommended by various authors for the estimation of scores, residual or basefree measures of change, and other kinds of difference scores are examined. A procedure proposed by Lord is extended to obtain more precise estimates, and an alternative to the Tucker-Damarin-Messick procedure is offered. A consideration of the purposes for which change measures have been sought in the past leads to a series of recommended procedures which solve research and personnel-decision problems without estimation of change scores for individuals.