Preconditions for sensitivity in measuring change: visual analogue scales compared to rating scales in a Likert format.
In a study of preconditions of responsiveness, we examined the variances obtained by two different ways of responding to questionnaire items. Subjects were 168 first-year medical students. They all completed a questionnaire of nine items. The original Likert-like scoring was (partially) replaced by visual analogue scoring in three quarters of the questionnaires. For three items the analogue form had a significantly greater variance than the discrete form, but no discrete item had a significantly greater variance than its analogue counterpart. Assuming that a greater variance was indicative for a greater responsiveness, our findings provide some support for the preferred use of analogue scales over discrete response categories in the measurement of changes over time.
Pfennings
L
L
Department of Medical Psychology, Vrije Universiteit, Amsterdam, The Netherlands.
Cohen
L
L
van der Ploeg
H
H
D000328:Adult; D001294:Attitude to Health; D005260:Female; D006801:Humans; D008297:Male; D010147:Pain Measurement / Q000706:statistics & numerical data*; D010555:Personality Inventory / Q000706:statistics & numerical data*; D011594:Psychometrics; D011788:Quality of Life; D012016:Reference Values; D015203:Reproducibility of Results; D013315:Stress, Psychological / Q000150:complications; D013337:Students, Medical / Q000523:psychology*