In the original published version of the paper,

Crossley, S., McNamara, D., Baker, R.S., Wang, Y., Paquette, L., Barnes, T., Bergner, Y. (2015) Language to Completion: Success in an Educational Data Mining Massive Open Online Course. Proceedings of the 8th International Conference on Educational Data Mining, 388-391.

One finding, the relationship between outcomes and the meaningfulness of words in discussion forum posts, was originally reported in the inverse direction of the correct direction.

This error is corrected in the version of the paper here