Introduction Physician global assessments of disease activity (medical doctor (MD) globals) are important outcomes. MD globals may vary based on their age, gender, practice setting and experience (number of patients seen per year and years in practice).

Methods We determined the variability of MD globals, surveying rheumatologists from the Canadian Rheumatology Association using rheumatoid arthiritis (RA) cases rated by MD for disease activity from 0 to 10. Cases were developed to span the spectrum of disease activity. Kappa, intraclass correlation (ICC) coefficients and linear mixed models were used.

Results 109 responded to the survey (approximately 30% response). The range of MD globals for the same scenario was as high as 7.6 out of 10, indicating vast discrepancies between physicians. Some scenarios outlined changes in individual patients; however, physicians surveyed were often in disagreement as to how much the patient recovered or worsened but the direction was the same (ie, if better all agreed). When physician-related factors were analysed separately, MD global scores were significantly influenced by age and experience (ranked by a physician, number of patients seen per year and years in clinical practice) in linear mixed models. Multivariate analysis revealed borderline significance for two age categories (56–65 years, P=0.049; over 65 years, P=0.058) and those who have seen 600–800 patients per year (P=0.056).

Conclusions This emphasises the need to establish evaluation criteria in RA for disease. Perhaps, a catalogue of patient scenarios that range from 0 to 10 could be developed, standardised and agreed on to decrease the wide variability of ranking by rheumatologists.