Why do students leave exams early?
It's simply just irrational.
I took my final for my applied statistics class earlier today. It wasn't very hardāI worked leisurely, triple-checked all of my answers, and still finished with a few minutes to spare on the 2-hour exam. But I was still very surprised by something:
Over 50% of the class turned in their exam and left before I did. Which doesn't really make any sense at all.
Each of the two midterm exams lasted 50 min. The final lasted 2 hours. I spent around 1.5 hours on each of the thirteen homeworks, around 1 hour studying/doing each of the 10 quizzes, and around 11 hours on a group project. If we plug in the grade distribution from the syllabus, we get this nice table:
| Item | Weight | Time Spent (min) | % of Final Grade PER Minute |
|---|---|---|---|
| final | 25% | 120 | 0.208 |
| midterm 1 | 20% | 50 | 0.400 |
| midterm 2 | 20% | 50 | 0.400 |
| homeworks | 20% | 1170 | 0.017 |
| quizzes | 10% | 660 | 0.015 |
| group project | 5% | 660 | 0.008 |
| sum | 100% | 2710 | 0.037 |
Therefore, in my applied statistics class, each minute I spent on an exam was at least 10x more impactful to my final grade than each minute I spent on a homework or quiz. This "time/impact imbalance" holds in almost all college classes. Every minute you spend on an exam has dramatically more weight on your final grade than every minute you spend studying or doing homework.
You might say "well, Nathan...maybe you were in the exam hall for longer than average because before the final, you were performing worse than the class average, and thus you needed a higher score on the final to secure a solid grade."
That would be a great argument, except I was in a better position to get an A than at least 50% of the class:
- my homework/quiz grades: slightly above the mean
- my midterm grades: well above the mean (my avg: 92, class mean: 78)
- my group project: ungraded (lol) but only 5% of final grade
So why did 50%+ of the class still leave the final before I did? I chalk it up to:
- Wanting to be done early ("This is my last exam [this week/this month/before break]. I think I did a good enough job, so I'm just gonna turn it in.")
- High confidence on exam performance ("That was so easy and I finished super early! I'm gonna go turn it in early
to flex how cool I am.") - Very low confidence on exam performance ("This is so hard. I'm so discouraged and probably not going to get anything else right, so I'll just turn it in.")
Those reasons are irrationalāassuming the goal is grade optimization. When an exam, on a per-minute basis, has such a large impact on your final grade, why would you leave the exam early?[1] I can only think of two reasons: you are very confident you (1) got a perfect score or (2) your performance will give you a good grade.
But humans, especially college students, are irrational. It's foolish to expect an average college student to make rational decisions. We don't. But I can try to help the status quo by writing this article! Send this article to your favorite college student ;)
A key assumption in my argument is that the marginal benefit of spending more time on an exam is always nonnegative, unless you tend to self-sabotage yourself (which is a rare case). While the marginal benefit is diminishing, the approximate 10x or even 20x multiplier (relative to HW/quizzes) is just so powerful. Catching even just a couple of points of mistakes on an exam has a disproportionately large impact on your course grade. ā©ļø
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