IMPLICATIONS OF THE TRUE SCORE MODEL IN ASSESSMENT OF MOOD STATE

Several investigators have used the Profile of Mood States (POMS) to assess general mood states. In these studies, POMS scores have been used as pre- and post-intervention assessments, with changes in mood states being attributed to the intervening factor. We propose that such use may be inappropriate relative to true score theory, particularly in the absence of adequate control groups. To demonstrate that single-administration assessments of current mood states cannot be considered indicative of stable mood patterns, we compared single-administration scores to average mood state measures derived from 18 separate assessments collected over three days. Results suggested that single-assessment values are significantly different from multiple-assessment averages and that the standard error of the measure is such that single-administration scores cannot be confidently interpreted.