The study analysed the Visual Analogue Scale (VAS), the Verbal Rating Scale (VRS) and the Numerical Rating Scale (NRS) to determine: 1. Were the compliance and usability different among scales? 2. Were any of the scales superior over the other(s) for clinical use?

A systematic review of currently published studies was performed following standard guidelines. Online database searches were performed for clinical trials published before November 2017, on the comparison of the pain scores in adults and preferences of the specific patient groups. A literature search via electronic databases was carried out for the last fifteen years on English Language papers. The search terms initially included pain rating scales, pain measurement, pain intensity, VAS, VRS, and NRS. Papers were examined for methodological soundness before being included. Data were independently extracted by two blinded reviewers. Studies were also assessed for bias using the Cochrane criteria.

The initial data search yielded 872 potentially relevant studies; of these, 853 were excluded for some reason. The main reason for exclusion (33.7%) was that irrelevance to comparison of pain scales and scores, followed by pediatric studies (32.1%). Finally, 19 underwent full-text review, and were analysed for the study purposes. Studies were of moderate (n=12, 63%) to low (n=7, 37%) quality.

All three scales are valid, reliable and appropriate for use in clinical practice, although the VAS is more difficulties than the others. For general purposes the NRS has good sensitivity and generates data that can be analysed for audit purposes.