Several studies have tried to quantify the differences in severity levels between raters working for the same assessments. Their results show that interindividual differences in severity levels are often important, regardless of the assessment situations. However, few studies have modeled the longitudinal evolution of intra-individual severity levels, and even fewer have compared the ratio between the intra- and interindividual differences. This paper seeks to remedy this lack of knowledge by comparing the ratio between the intra- and interindividual severity levels of six raters, who worked together, from September 2011 to April 2014, as raters for the oral expression test of the Test d’évaluation du français adapté au Québec (TEFAQ). Those six raters assessed the performance of 4,083 candidates and their severity levels were estimated using the multi-facet Rasch model. Five raters dyads were modeled during five distinct periods, totaling from 11 to 38 time points, and their severity levels were estimated from once to four times per month. This allowed us to calculate, for each period, an intra-individual and interindividual severity range and these ranges were then compared to obtain a ratio showing whether a given rater’s severity level fluctuates as much over time as it does when compared to the severity level of their peer. Results show that, overall, the intra-individual differences are as high as the interindividual ones, with a median ratio of 0.97, despite the small number of raters modeled. The practical impacts of those results are then discussed, as well as the methodological and conceptual limits of this study.