A trick I learned from Adam Hesterberg.


Problems run the gamut in difficulty. Some are very difficult, and even a slight step towards a solution is hailed as a breakthrough. Some are medium difficulty, and a moderate sized step is needed to be considered a breakthrough.

Finally, sometimes a problem is so easy that no one pays it any more mind, but the problem is still not closed completely.

Today, I'm going to explain an incredibly clever trick for grading True and False questions which belongs to the third category of these.


In Gradescope, a widely used piece of grading software, when grading a question you can type number keys (0, 1, 2,) to give points on a question. How do you grade a true / false problem which contains of 7 true or false questions.

The natural way is to assign +2 to each question, and give points to each item if you solve it. However, a better way is to give +2 for True, when the answer is True, and -2 for True when the answer is False. After adding a baseline score (to ensure that the score is right when all answers are False), this now lets one grade problem sets by simply pressing the digits corresponding to true answers.

The reason this is faster for humans (despite requiring, in theory, the same number of keystrokes) is that you don't have to store the answers in memory, and can just type the numbers corresponding to Trues.

It's a reminder that even things that are computationally identical to computers can be very different for humans. In terms of complexity theory, this algorithm allows for no memory requirements on the human's behalf.

Some FAQs

Why don't you use a scantron or a form? Gradescope is the dominant system, and while it does support true / false that would require a separate component.