Administering selected subscales of patient-reported outcome questionnaires to reduce patient burden and increase relevance: a position statement on a modular approach

Patient-reported outcome (PRO) questionnaires considered in this paper contain multiple subscales, although not all subscales are equally relevant for administration in all target patient populations. A group of measurement experts, developers, license holders, and other scientific-, regulatory-, payer-, and patient-focused stakeholders participated in a panel to discuss the benefits and challenges of a modular approach, defined here as administering a subset of subscales out of a multi-scaled PRO measure. This paper supports the position that it is acceptable, and sometimes preferable, to take a modular approach when administering PRO questionnaires, provided that certain conditions have been met and a rigorous selection process performed. Based on the experiences and perspectives of all stakeholders, using a modular approach can reduce patient burden and increase the relevancy of the items administered, and thereby improve measurement precision and eliminate wasted data without sacrificing the scientific validity and utility of the instrument. The panelists agreed that implementing a modular approach is not expected to have a meaningful impact on item responses, subscale scores, variability, reliability, validity, and effect size estimates; however, collecting additional evidence for the impact of context may be desirable. It is also important to recognize that adequate rationale and evidence (e.g., of fit-for-purpose status and relevance to patients) and a robust consensus process that includes patient perspectives are required to inform selection of subscales, as in any other measurement circumstance, is expected. We believe that the considerations discussed within (content validity, administration context, and psychometric factors) are relevant across multiple therapeutic areas.