Writing achievement is a complex skill set as characterized by the sociocognitive writing framework, including writing domain knowledge (e.g., sentence structure), general cognitive skills (e.g., critical thinking) and intra- (e.g., interest) and interpersonal (e.g., collaboration) subfactors. During students' postsecondary careers, they need to write in different genres. Yet, we have limited understanding about the contribution of genre mastery to students' writing achievement, which can affect their broader success (e.g., GPA). Partnering with six, diverse 4-year universities, we collected student responses to a "standardized" writing assessment and "authentic" course writing assignments which were coded for "genre" as: "standardized," "persuasive," "inform/explore," and "reflective." Using automated writing evaluation, we extracted approximately 50 linguistic features (e.g., vocabulary usage) from the 1,426 writing samples. We present findings for genre-based feature distributions, cross-genre correlations, and implications for postsecondary writing education. [This paper was published in: "Companion Proceedings in the 10th International Conference on Learning Analytics & Knowledge (LAK20)" (pp. 53-55). LAK20.]