OBJECTIVES: Electronic data capture of patient-reported outcomes (ePRO) offers efficiency, greater accuracy and improved compliance vs paper. However, mode equivalence and device usability needs to be demonstrated, per ISPOR ePRO Research Guidelines. Mode equivalence between paper and electronic versions of the EORTC Quality of Life Questionnaire (EORTC QLQ-C30;v3.0) and its Breast Cancer Module (QLQ-BR23;v1.0) was evaluated, as well as their usability on two electronic devices with different screen sizes. METHODS: Adult women with metastatic breast cancer (mBC) who had not received chemotherapy for metastatic disease were screened. Using an alternating crossover study design, half completed questionnaires on paper first, followed by a tablet (10.1″screen) and a handheld (4.5″screen); the other half used the handheld first, followed by tablet and paper. To optimize recall, the think-aloud method was used and cognitive debriefing interviews were conducted after each questionnaire was completed on each device. Usability questions were asked after completion of both questionnaires on a device. RESULTS: