This article examines the basic premises underlying the formula converting R scores into cumulative percentage grades. Since 2003, this method is used by Québec universities ranked in MacLean’s magazine. However, the scope of this conversion formula largely exceeds the simple classification of institutions for which it was conceived. In fact, Cegep students are seriously disadvantaged when their cumulative average is compared to that of high school graduates from other Canadian provinces. To be equitable, the R score-to-percentage conversion method should be used each time the grades of Cegep graduates are compared to those of their high school peers elsewhere in Canada during the admission process (access to limited enrolment programs, eligibility for bursaries based on merit or achievement awards) or as a measure to compare the performances of educational institutions or systems.