A growing number of clinical trials employ electronic media, in particular smartphones and tablets, to collect patient-reported outcome data. This is driven by the ubiquity of the technology, and an increased awareness of associated improvements in data integrity, quality and timeliness. Despite this, there remains a lingering question relating to the measurement equivalence of an instrument when migrated from paper to a screen-based format. As a result, researchers often must provide evidence demonstrating the measurement equivalence of paper and electronic versions, such as that recommended by the ISPOR ePRO Good Research Practices Task Force. In the last decade, a considerable body of work has emerged that overwhelmingly supports the measurement equivalence of instruments using screen-based electronic formats. Our review of key works derives recommendations on evidence needed to support electronic implementation. We recommend application of best practice recommendations is sufficient to conclude measurement equivalence with paper PROMs. In addition, we recommend that previous usability evidence in a representative group is sufficient, as opposed to per-study testing. Further, we conclude that this also applies to studies using multiple screen-based devices, including bring-your-own-device, if a minimum device specification can be ensured and the instrument is composed of standard response scale types.
