Wiriyakijja P, et al. – This study was designed not only to investigate the range of existing patient–reported outcome measures (PROMs) used in studies of recurrent aphthous stomatitis (RAS) but also to assess their quality properties via the assessment of psychometric properties and interpretability. It was observed in the findings that there was a wide range of PROMs used in clinical studies of RAS. However, the majority of these PROMs lack evidence of measurement properties and interpretability for RAS patients.