Spanish versión of The App Behavior Change Scale (ABACUS-Es): Adaptation and validation study

Health applications have grown exponentially in the last decade and are well accepted by users and health services. It is essential that digital tools meet the needs of the target users and are reliable, hence the importance of evaluating them. The aim of this study was to adapt The App Behavior Change Scale (ABACUS) into the Spanish language and to assess their metric properties. This was an study undertaken in two phases: (1) translation and cultural adaptation process; (2) psychometric evaluation. 65 physical activity apps were included in the study (9 running Apple, 50 running Android and 6 running both). Cross-cultural adaptation, translation, and metric evaluation was made. The internal consistency and test-retest reliability of the Spanish version of the ABACUS was evaluated using physical activity apps. Two reviewers independently rated the apps using the translated scale. The apps were then rated again 2 weeks later by the same reviewers to measure test-retest reliability. No major differences were observed between both versions of ABACUS (original and Spanish). Discrimination indices (item-scale correlation) obtained appropriate results for both raters. ABACUS-Es presented an excellent interrater reliability (0.82, 95% CI 0.80-0.84) and excellent internal consistency (Cronbach alpha = 0.82). The Spanish version of ABACUS, ABACUS-Es, is an instrument with adequate metric properties to measure the potential behavior change of apps from health professionals and app developers. ABACUS will help guide future research efforts in the development and evaluation of apps to promote health behaviors, and provides guidance for app developers to include adequate behavior change techniques in apps in Spanish to be used to promote health behaviors.