AN APP for the Assessment of Pain Intensity: Validity Properties and Agreement of Pain Reports When Used with Young People

Objective Painometer is a mobile application that includes four pain intensity scales: the Numerical Rating Scale, the Faces Pain Scale‐Revised, the mechanical visual analogue scale and the Colored Analogue Scale. The aim of this study was to analyze the validity and agreement of the intensity reports provided by these scales and their traditional counterparts. Methods Participants were 180 young people (mean age = 14.88; SD= 1.64; age range: 12–19). They were asked to report the maximum intensity of their most frequent pain in the previous three months using traditional and electronic versions of the scales. They also reported their level of fatigue and pain catastrophizing. Construct validity was evaluated by confirmatory factor analysis (CFA) and by convergent and discriminant validity. Criterion validity was assessed as concurrent validity. Agreement was calculated using the Bland and Altman method. Analyses were conducted for two confidence intervals (CI): 95% and 80%. Results CFA demonstrated that the four electronic versions of the scales measure a single factor. All the scales showed a) moderate to high convergent validity, b) adequate discriminant validity with fatigue ratings, and c) adequate concurrent validity with pain catastrophizing ratings. Results also show that traditional and electronic versions of the four scales are in agreement, at least at the 80% CI. Conclusions Our results demonstrate that pain intensity scores reported with the scales in Painometer are valid, and concordant with their traditional counterparts.