'We're Not Going to Start Lifting Stones Now…': Stakeholder Perspectives on the Role of Psychometric Methods in Outcome Measurement.

OBJECTIVES:Psychological outcome measures guide research and clinical decision-making, yet many widely used tools were developed with limited psychometric rigour. Although advanced methods (e.g., item response theory, structural equation modelling) are now widely available, their added value in applied research remains uncertain and applied researcher perspective regarding such are unexplored. We aimed to address this gap in knowledge by examining key stakeholder perspective. METHOD:To explore how these methods are perceived, we conducted semi-structured interviews with 21 stakeholders spanning psychometrics, clinical practice, applied research, statistics and academia. Data were analysed using reflexive thematic analysis. RESULTS:Analysis identified three overarching themes: (1) growing recognition that heterogeneity in latent traits challenges assumptions underlying many measures, (2) the enduring use of entrenched but psychometrically weak tools and (3) nuanced views on when advanced methods meaningfully influence research findings. Participants acknowledged gaps in psychometric literacy and emphasised the need for more training and collaboration with psychometricians. CONCLUSION:These findings highlighted persistent limitations in measurement practice, clarify contexts where psychometric methods add genuine value, and point to opportunities for strengthening outcome measurement in psychology and psychiatry research.