Assessing Mood Change With Visual Analogue Scales: Composite Versus Vectorial Approaches

Abstract

We examined the assessment of mood change using multiple visual analogue scales from the perspectives of computing a composite difference score and verifying the vectorial comparability of test and retest ratings. The composite approach raises the question of whether the true score can measure mood and whether valid conclusions can be derived from true-score differences within individual data. The vectorial approachallows clinicians to use the data to test the causal and functional conception of ordinal measurability of patients' mood. This falsificationistapproach may lead clinicians to recognize that, in some cases, ratings are not measurements and should be treated as speech acts in a conversational setting