When assigning a late penalty for assignments, is that penalty subtracted from the total or does it reduce the student's score by that percentage.

Ex: Assignment is worth 10 points and the late penalty is 20%

Student A hands it in late, getting all questions correct (base score of 10); they get 80% in either circumstance

Student B hands it in late, getting half of the questions correct (base score of 5); do they get 3/10 (subtract 20% of the total from their score) or do they get 4/10 (reduce their score by 20% of it's original value)?

Student C hands it in late, getting only 1 question right (base score of 1); do they get -1/10, 0/10, or 0.8/10?

Which is the most reasonable late penalty? Or at least which one has better outcomes?

  • 7
    $\begingroup$ Are you asking which of these is the most reasonable late penalty, or are you asking how grading penalties work? In general, how an individual instructor interprets "late penalty of 20%" depends on the instructor. It's not entirely defined by that phrase. $\endgroup$
    – Opal E
    Apr 14, 2020 at 17:39
  • $\begingroup$ Which is the most reasonable late penalty? Or at least which one has better outcomes (possibly, pros and cons of each) $\endgroup$ Apr 14, 2020 at 17:56
  • 2
    $\begingroup$ @JoelBoulet: Welcome to matheducators.SE! When people ask for clarifications on a question, it's best if you edit the question rather than providing the clarifications in comments. $\endgroup$
    – user507
    Apr 15, 2020 at 0:51
  • 1
    $\begingroup$ The best outcome of a late penalty is that they avoid it and turn in their work on time. The next best outcome is that it works for the next assignment. The exact formula probably doesn't matter too much; just as long as it gets their attention. $\endgroup$
    – Adam
    Apr 16, 2020 at 0:29

2 Answers 2


The most common is the straight X% off, not the proportional one. I would also say it is the fairest. Plus it's simpler. (Obviously, once you are at zero, don't go negative though. But I have had assignments zero-ed from being several days late.)


Which is the most reasonable late penalty?

I would argue that the most reasonable late penalty is to simply get no grade on the assignment at all (i.e., score is null, or 100% penalty). This makes the most efficient use of the instructor's time.

  • Instructor does not have to chase students after the fact to submit late assignments.
  • Instructor does not have to re-set grading framework (pull out books, answer sheet, programming test suite, software grade book website, etc.) to restart grading.
  • Instructor does not have to spend time debating/calculating the percent off penalty, as shown in this question.
  • Instructor can spend added time working on improved presentations for students who did submit the assignment.
  • Instructor can scan assignments for plagiarism (by hand, TurnItIn, MOSS, etc.) in a single batch process, and not re-do the step at a later date.
  • Instructor can immediately distribute answers, results, and feedback the next day, so as to capitalize on the lessons while they're fresh.
  • The motivation for students submitting the assignment on time is maximized.

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