Creating a rubric to deduct points based on errors: can it be done?

[mprogers]

My students typically make several common errors on each of the questions in an assignment. I would like each line of the rubric, representing one question, to allow me to mark each error, and get appropriate points deducted. 

Suppose I have a 10 point question, and have identified 3 errors that students typically make:

error 1 - lose 2 points; error 2 - lose 4 points; error 3 - lose 1 points

So the rubric would show

Criteria       Out of      Errors

Question 1 : [10]         Error 1: [ ] Error 2: [ ] Error 3: [ ]

I would be able to check each error, and the sum would be deducted, e.g.,

Criteria       Out of      Errors

Question 1 : [7]            Error 1: [✅ ] Error 2: [ ] Error 3: [✅ ]

I could set up 2**3 = 8 different ratings, which is doable but a pain (and if I have 5 errors, it'd be up to 32, totally unreadable). I could also just create one criterion per error, but that would lead to a ridiculously lengthy rubric; and each set of errors is really specific to each question.

Any ideas? Shouldn't the rubric allow that, or am I the only person who grades like this?

[James · Accepted solution]

@mprogers 

What you ask for is not possible with Canvas' rubric offering. The whole rubric selection is based on selecting a single rating within a criteria. To do anything else would be a substantial reworking of the rubric system. Canvas is undergoing one of those right now with Enhanced Rubrics, but it still is based on the premise that you will not select more than one rating for any criteria.

Canvas isn't setup to take points off, only to award points. There have been some hacks to allow negatives, but nothing like what you're wanting.

I agree that adding multiple criterion for each rating makes for a really long rubric.

I've done some similar things, but always for the overall comments rather than the individual criteria comments. I tried not to use those because (at the time) they were hard for students to find so they weren't seeing them.

One possibility is to use the comments for each criteria to explain what points the student got. Give the students the score they deserve and then leave a comment. You would probably want to switch to freeform comments so that the individual ratings aren't shown (they won't make sense since you cannot select more than one). What I would do is set up a spreadsheet that has the text that I would leave in a comment and then put in the numbers of the errors. For example, I could type 13 and it would give me the code for messages 1 and 3.

Here's an example of three criteria. I would enter the code in column A and then copy/paste the message from column B.

The formula in cell G2 is =IF(ISNUMBER(FIND(G$1,$A2)),D2,"")

It gives the value in cell D2 if the number at the top of the column is found in cell A2 and blank if not. I then copied that over and down for the other rows.

In cell B2, the formula is =TEXTJOIN("; ",TRUE,G2:I2)

That joins the messages in cells G2 through I2 together with a semicolon and space, ignoring any that aren't present. I copied that down for each criteria.

You could modify things to calculate the score so you don't have to, but I didn't want to get too technical if this solution isn't worth it.

If you wanted to use the overall comment (so there is less copy/paste) than individual comments,  you could score the entire rubric in the spreadsheet and the combine the comments in column B with another textjoin(), I would add the text of the criterion in there so students knew which one you were talking about.

With freeform comments, you can add the comments to your comment bank. Then you could just select them from the list the next time you need them. However, there's no way to delete comments that you don't want to use anymore so some people find that more hassle than it's worth.

Another possibility is to leave the ratings visible so students could see how many points they were worth. The point value would need added to the description since putting them in the point values for the ratings would cause them to shift in order and you would need different point values for each. You would need to type in the points, but then your comment could be something simpler such as "Errors 1 and 3".

What you are doing does not work well with rubrics or SpeedGrader.

If it were me and I had to do it this way, I would write a program that would take the results of the spreadsheet and complete the rubric programmatically outside SpeedGrader.

If it were me and I didn't have to do it this way, I would explain all of the common errors in a document or video that I made the students aware of ahead of time and then lower the complexity of the rubric. When students had questions about their grade, I referred them to the existing documentation.

What I found (I taught college level math) is that the vast majority of my students didn't care about the grade and feedback nearly as much as I did. The copious feedback I provided often went unread and definitely unheeded. By about week 11 (out of 16), my comments would get shorter because those making the same mistake week after week weren't changing.

I taught face-to-face, so I would sometimes ask the students why they didn't follow the directions. A common complaint was that they didn't read the directions because they were too long. Those students weren't reading the feedback, either, because it was also too long. Finding that happy medium between enough info to be helpful and not so much that it goes unread can be challenging.