Otis reports that he began research for his paper a few weeks before it was due but he didn't begin drafting until three days before he turned it in. He says he spent enough time on it because he "didn't feel rushed."
Otis's paper is in the first quartile for length--1192 words to his class's median of 1465. He has the lowest rate of surface errors in his class, but he's in the third quartile for problems with evidence. Otis does report proofreading.
A lack of sentence variety might partially explain Otis's lack of surface errors. But the fact that he tends to have overlong subjects with short verbs suggests to me that he's attempting an academic voice, even if it isn't one that his instructors appreciate. Another explanation is that Otis actually proofread his paper, despite putting it off. I still haven't crunched the numbers to see if procrastination makes one less likely to proofread.
Unlike Mary and Mark, whose evidence problems centered on just a couple areas, Otis has several problems. His top two are no lead-ins for quotations and weak lead-ins for quotations. He only once uses a signal phrase and rarely sets up the quote in the previous sentence. His next most common problems are using quotations where paraphrase would be more appropriate and citing his "own" conclusions. I'm particularly interested in his habit of using quotations instead of paraphrase, because in Otis's class, this problem was much more common among procrastinators than non-procrastinators. (The same is not true for Mark and Mary's class, however.)
When I say that paraphrase would be more appropriate, I'm talking about quoting facts that are worded in unimpressive ways. My feeling is that students do this because they find paraphrase difficult or intimidating. Perhaps the original quote was difficult for the student to understand, so they couldn't put it in their own words. Or the student has been warned about the problem of paraphrasing incompletely, risking charges of plagiarism, so they simply resort to quotations to avoid that problem.
It's possible that spending more time on his paper would have helped Otis introduce his quotations better (as with Mary), but it seems unlikely that it would have prevented his dropped quotes (as with Mark). I could also imagine that spending more time would have helped him write more paraphrases, but that seems like a reach. He had plenty of evidence, he just didn't use it very well. Practice might help, but just writing for longer probably wouldn't have.