@QianYu That's interesting. That functionality definitely does not exist right now, but you could put in a feature idea.
So, using your grading method, if there were 4 options (3 correct, 1 incorrect):
- If I select none, I get 1 point (for not selecting the incorrect).
- If I select one incorrect and no others, I get 0 points.
- If I select one correct and no others, I get 2 points (1 for correct and 1 for not selecting the incorrect).
- If I select one correct and one incorrect, I get 1 point (1 for correct and 0 for selecting the incorrect).
- If I select two correct and no others, I get 3 points (2 for correct and 1 for not selecting incorrect).
- If I select two correct and one incorrect, I get 2 points (2 for correct and no penalty for selecting the incorrect).
- If I select all, I get 3 points (for correctly selecting the 3 correct and no penalty for selecting the incorrect).
- If I select the correct three and do not select the incorrect one, I get 4 points.
And using Canvas' current method, if there were 4 options (3 correct, 1 incorrect) and I made the question worth 4 points:
- If I select none, I get 0 points (for not selecting the correct answers).
- If I select one incorrect and no others, I get 0 points (because 0 is the lowest).
- If I select one correct and no others, I get 1.33 points (+1.33 for correct).
- If I select one correct and one incorrect, I get 0 points (+1.33 for correct and -1.33 for selecting the incorrect).
- If I select two correct and no others, I get 2.66 points (+2.66 for correct).
- If I select two correct and one incorrect, I get 1.33 points (+2.66 for correct and -1.33 for selecting the incorrect).
- If I select all, I get 2.66 points (+4 for correctly selecting the 3 correct and -1.33 for selecting the incorrect).
- If I select the correct three and do not select the incorrect one, I get 4 points.
In six of these scenarios, your grading system would lead to higher scores for the students, including giving them more point for selecting all of the answers and points for selecting no answers. (Just to be clear, I am not placing any judgement on this, just trying to think through the permutations.)
Now, using your grading method, if there were 4 options (1 correct, 3 incorrect):
- If I select none, I get 3 points (for not selecting the incorrect three).
- If I select one incorrect and no others, I get 2 point (2 for not selecting two incorrects).
- If I select two incorrects and no others, I get 1 point (1 for not selecting an incorrect).
- If I select three incorrects and no others, I get 0 points.
- If I select one correct and no others, I get 4 points (1 for correct and 3 for not selecting the incorrects).
- If I select one correct and one incorrect, I get 3 points (1 for correct and 2 for not selecting two incorrects).
- If I select one correct and two incorrects, I get 2 points (1 for correct and 1 for not selecting an incorrect).
- If I select all, I get 1 points (1 for correct).
And using Canvas' current method, if there were 4 options (1 correct, 3 incorrect) and I made the question worth 4 points:
- If I select none, I get 0 points.
- If I select one incorrect and no others, I get 0 points.
- If I select two incorrects and no others, I get 0 points.
- If I select three incorrects and no others, I get 0 points.
- If I select one correct and no others, I get 4 points (+4 for correct).
- If I select one correct and one incorrect, I get 0 points (+4 for correct and -4 for selecting an incorrect).
- If I select one correct and two incorrects, I get 0 points (+4 for correct and -4 for not selecting multiple incorrect).
- If I select all,I get 0 points (+4 for correct and -4 for not selecting multiple incorrect).
In this scenario, you give points for everything but selecting all of the incorrects and not selecting the correct one. Again, it is six scenarios where you are grading higher, but this time there are more opportunities for students to get points without selecting the correct one at all.
I could see this kind of grading being useful in certain scenarios, but would recommend reflection if thinking of applying it widely.