LIWC Research Series:
An analysis of over 50,000 college admissions essays from more than 25,000 entering students and their grades over four years of college, found that higher grades were associated with higher levels of language reflective of analytical thinking and personal narratives.
Pennebaker JW, Chung CK, Frazee J, Lavergne GM, Beaver DI (2014) When Small Words Foretell Academic Success: The Case of College Admissions Essays. PLoS ONE 9(12): e115844. https://doi.org/10.1371/journal.pone.0115844