OBJECTIVES: We examined which factors affect agreement between patient and clinician ratings of chronic plaque psoriasis (Ps) severity. METHODS: Scores from two patient (patient global impression of severity [PGIS] and demographic form [DF]), two clinician assessments of Ps severity (Physician Global Assessment [PGA] and Psoriasis Area Severity Index [PASI]), and patient demographic and health data (age, sex, race, ethnicity, education level, time since diagnosis, and general health status [GHS]) were pooled from two previously conducted studies. Patient and clinician assessments of severity responses were collapsed into categories of “mild”, “moderate”, and “severe” to facilitate comparisons between measures with differing numbers of response categories. Statistical analyses included logistic regression methods treating agreement between measures as the outcome and demographic, health data, and severity ratings as predictors. Logistic regression models were run twice, switching between patient- and clinician-rated severity. RESULTS: Data from 200 adults with Ps (mean age=46.2 years [standard deviation=12.8]; 50.0% female) were analyzed. Overall patient-clinician agreement ranged from 51.8% (PGIS/PASI)-78.0% (DHIF/PGA), with patients rating their Ps severity higher (vs. clinicians) in 9.5%-19.1% of instances; most of these ratings differed by only one grade (86.8%-94.4%). When controlling for clinician-reported severity, DHIF/PASI logistic regression demonstrated that higher education (some college+ vs high school diploma or less) was associated with a higher likelihood of severity agreement (odds ratio [OR]=2.627, 95% confidence interval [CI]=1.128 6.381) and a higher level of clinician-rated severity was associated with a lower likelihood of agreement (OR=0.651, 95% CI=0.435, 0.962). When controlling for patient-rated severity, results were similar for education level (OR=2.661, 95% CI=1.158, 6.382). CONCLUSIONS: Level of patient-clinician agreement differs between various measures. Care needs to be taken in selection of patient and clinician assessments of severity, given the different factors influencing patient- and clinician-reported disease severity.