Validation of a two-item short form of the perceived health competence scale

Perceived health competence is a construct encompassing individuals’ confidence in managing their health and health-related behaviors. The 8-item Perceived Health Competence Scale (PHCS-8), developed to measure this construct, has established psychometric properties including test-retest reliability and predictive validity for health behaviors and clinical outcomes. We aimed to validate the 2-item Perceived Health Competence Scale (PHCS-2), an abbreviated version of the PHCS-8, for use in clinical and research settings where respondent burden is a primary concern. We conducted a psychometric validation study using pooled data from 482 participants across two cohort studies conducted in an integrative medicine clinic. Participants completed the PHCS-8, PROMIS Global Health Scale (yielding physical and mental health T-scores), Socially Desirable Response Set Five-Item Survey (SDRS-5), and sociodemographic information. Psychometric evaluation included internal consistency reliability, exploratory factorial validity analysis, Bland-Altman analysis of instrument agreement, convergent validity through correlation analysis, and known-groups validity across demographic and health status subgroups. Study participants had a mean age of 51 years (SD = 13.2), were 81% female, and predominantly college-educated (86%). The PHCS-2 demonstrated appropriate response distributions with optimal inter-item correlation (r = 0.31) and factorial validity (factor loadings: 0.569, 0.522). Criterion validity was supported by strong correlation with the PHCS-8 (r = 0.80) and minimal systematic bias in Bland-Altman analysis (mean difference = 0.032, 95% limits: -0.792 to 0.856). Convergent validity was demonstrated through moderate correlations with PROMIS physical health (r = 0.463) and mental health (r = 0.391) T-scores. Known-groups validity was confirmed by significant differences between individuals with above-average versus below-average physical health (Cohen’s d = 0.92) and mental health (Cohen’s d = 0.62). Discriminant validity was supported by no significant correlation with social desirability (SDRS-5, r = 0.013, p > 0.05). The PHCS-2 represents a psychometrically sound, brief measure of perceived health competence that maintains strong concordance with the full PHCS-8 while substantially reducing respondent burden. This validated instrument provides an efficient clinical screening method to identify patients with lower perceived health competence who may benefit from targeted self-management support interventions.