Usability evaluation of ambient assisted living systems using a multi-method approach

Background -- The assessment of the usability of Ambient Assisted Living (AAL) products and services is a demanding process due to their complexity. Objective -- To verify the feasibility of using a multi-method approach for data collection when evaluating the usability of AAL products and services. Methods -- An experimental study was conducted using two questionnaires, the Post-Study System Usability Questionnaire (PSSUQ) and the International Classification of Functionality, Disability and Health based Usability Scale (ICF-US), together with the registration of quantitative data related to the performance of the users carrying out specific tasks, and the registration of critical incidents. Results -- The experimental results suggest that the PSSUQ (to determine self-perceived usability) and the ICF-US (to determine the opinion of the evaluator on the users' performance) promote an accurate evaluation of the interaction mechanisms. Conclusion -- Multiple data collection methods seems to be an efficient approach for usability evaluation of AAL products and services.