There is a large body of research on the effectiveness of rater training methods in the industrial and organizational psychology literature. Less has been reported in the measurement literature on large-scale writing assessments. This study compared the effectiveness of two widely used rater training methods--self-paced and collaborative frame-of-reference training--in the context of a large-scale writing assessment. Sixty-six raters were randomly assigned to the training methods. After training, all raters scored the same 50 representative essays prescored by a group of expert raters. A series of generalized linear mixed models were then fitted to the rating data. Results suggested that the self-paced method was equivalent in effectiveness to the more time-intensive and expensive collaborative method. Implications for large-scale writing assessments and suggestions for further research are discussed.