"not one size fits all" The challenges of measuring paediatric health-related quality of life and the potential role of digital ecological momentary assessment: a qualitative study.

Purpose: To explore the views of clinicians and researchers about the challenges of measuring health-related quality of life (HRQoL) in children (5-11 years) and to explore whether digital ecological momentary assessment (EMA) could enhance HRQoL measurement.

Methods: Semi-structured qualitative interviews with 18 professionals (10 academics/researchers, four clinicians, four with both professional backgrounds) experienced in child HRQoL measurement. We analysed data thematically.

Results: Theme One describes the uncertainty around conceptualising HRQoL for children and which domains to include; the greater immediacy and sensitivity of children's reflections on their HRQoL, leading to high variability of the construct; and the wide individual differences across childhood, incongruent with fixed HRQoL measures. Theme Two describes the challenges of proxy reporting, questioning whether proxies can meaningfully report a child's HRQoL and reflecting on discrepancies between child and proxy reporting. Theme Three covers the challenge of interpreting change in HRQoL over time; does a change in HRQoL reflect a change in health, or does this reflect developmental changes in how children report HRQoL. Theme Four discusses digital EMA for HRQoL data capture. In-the-moment, repeated measurement could provide rich data and address challenges of recall, ecological validity and variability; passive data could provide objective markers to supplement subjective responses; and technology could enable personalisation and child-centred design. However, participants also raised methodological, practical and ethical challenges of digital approaches.

Conclusion: Digital EMA may address some of the challenges of HRQoL data collection with children. We conclude by discussing potential future research to explore and develop this approach.