“What does THIS Mean?”: A Collaborative Expert Evaluation of Health Data Representations for Older Adults

Health Data Representations (HDRs) pose significant accessibility problems for people with disabilities and older adults, particularly those with visual, hearing, speech, motor and cognitive impairments, as well as literacy problems. While methodologies like heuristic evaluation and visualisation literacy are valuable, they have limitations in addressing the varied and nuanced range of data representations and perceptual matching issues. This paper presents findings from a collaborative expert evaluation that strategically bridges the gap between domain experts and non-experts. By scoping out representative HDRs, our approach significantly expands the research space for accessibility issues within the designated scope, narrowing critical gaps in existing independent guidelines. Using this methodology, we carefully examined common conventional HDRs, collaborating with experts to identify 179 potential issues specific to older adults. Categorisation strategies highlighted key issues within this broad problem space, showing that existing guidelines fail to effectively address all of the predominant categories. Our paper presents a set of emerging impairment-agnostic recommendations in response, embedding crucial steps towards mitigating these problems. Our study not only identifies challenges but also provides a model for iterative evaluation and adaptation of critical HDR. Beyond informing more accessible system design, we also highlight innovative opportunities for future HDRs.