The relationships of quantitative measures of writing skills to overall writing quality as measured by the E.T.S. Composition Evaluation Scale (CES) were examined. Quantitative measures included indices of language productivity, vocabulary diversity, spelling, and syntactic maturity. Power of specific indices to account for variation in overall writing quality was examined through use of multiple regression analysis. Subjects were 983 students in grades four, six, nine, and twelve; they were chosen from 20,000 participants in the Virginia Educational Needs Assessment Project who comprised a stratified random sample of 57 of Virginia's 140 school divisions. Subjects were matched on sex and levels of ability and achievement so that this sample resembled a nationwide rather than a statewide sample. Results of the correlation analysis indicated that quantitative and qualitative measures of writing skills are significantly related. Results of multiple regression analysis indicated that sizable amounts (from 21 percent to 57 percent in this study) of the variation in the qualitative assessement of writing performance can be accounted for by using the following quantitative predictors: total words written, total sentences written, percentage of unique words written, percentage of unique words misspelled, and number of words per T-unit. (Author/MV)