The Positive Psychology Outcome Measure (PPOM) for people with dementia: Psychometric properties and factor structure

Objectives: To conduct an in-depth psychometric assessment of the PPOM; a measure of hope and resilience. Method: An observational study at five NHS trusts across England. Participants either completed the study using self-complete or interview led procedures, depending on their preference. Assessments were internal consistency, floor and ceiling effects, test-retest reliability, convergent validity and factor structure. Results: 225 participants were recruited and completed the study, with a subsample of 48 comprising the test-retest sample. Internal consistency was excellent alpha=0.94, and significant correlations were observed between quality of life (r=0.627, p<.001), depression (r=-0.699, p<.001) and the Control, Autonomy, Self-realisation and Pleasure Scale (CASP-19; r=0.73, p<.001). The PPOM remained moderately stable over a one week period (ICC: 880) and factor analyses indicated a two-factor structure solution with acceptable fit indices. Discussion: The PPOM has robust psychometric properties and is now suitable for use research and practice. People who met the clinical criteria for depression were more likely to have lower scores on the PPOM, indicating criterion validity. Future work is needed to establish the PPOM as sensitive to change and to investigate the relationship between hope, resilience and depression further.