Communal factors in rater severity and consistency over time in high-stakes oral assessment

This article focuses on rater severity and consistency and their relation to major changes in the rating system in a high-stakes testing context. The study is based on longitudinal data collected from 2009 to 2019 from the second language (L2) Finnish speaking subtest in the National Certificates of Language Proficiency in Finland. We investigated whether rater severity and consistency changed over that period and whether the changes could be explained by major changes in the rating system, such as the change of lead examiner, the modus of rating and training (on-site or remote), and the composition of the rater group. The data consisted of 45 rating sessions with 104 raters and 59,899 examinees and were analysed using the many-facet Rasch model and generalized linear mixed models. The analyses indicated that raters as a group became somewhat more lenient over time. In addition, the results showed that the rater community and its practices, the lead examiners, and the modus of rating and training can influence rating behaviour. Finally, we elaborate on implications for both research and practice.