The study applied the Multi-Dimensional analysis used by Biber (1988) to examine the functional parameters of essays. Co-occurrence patterns were identified within an essay corpus (n=1529) using a linguistic indices provided by Co-Metrix. These patterns were used to identify essay groups that shared features based upon situational parameters. Results revealed that linguistic features reliably co-occurred according to the parameters. Namely, four dimensions were interpreted and associated with essay quality, prompt, and grade level. Confirmatory analyses revealed that the dimensions reliably distinguished among the parameters. Results provide insight into the situational parameters that affect writing, and the extent to which essays vary among between themselves. The results have important implications for composition and between themselves. The results have important implications for composition pedagogy, writing assessment, and writing theory. [This is a contribution from: T. Berber and M. Veirano Pinto (Eds.), "Multi-Dimensional Analysis, 25 Years on. A Tribute to Douglas Biber" (p197-237). John Benjamins Publishing Company, 2012.]