BACKGROUND: Health research apps often do not focus on usability as a design priority. This is problematic when the population of interest is disproportionately underrepresented as users of mobile apps, especially observed with aging older adults (> = 75). Challenges with the adoption of health information technology (HIT) among this group are exacerbated by poor design and user interface/experience (UI/UX) choices. This protocol describes the testing and evaluation process of one HIT app for the family-based collaboration platform InfoSAGE.