How can you include a negative value in a Canvas rubric, such as a deduction for certain errors or for missing a time target in a presentation.
When I looked into this before, it appeared that the -1 was a programming decision rather than a deliberate attempt to limit the negativity to -1. They initialize the value to -1 since it's not possible to have negative points and then scan through the items. If it comes back as -1, then we know it's not set. It reminds me of programming from the 80's where we would set a value to something that couldn't happen, like 999 and then look for the minimum or -999 and then look for the maximum. The first value found would always override the initial value, so as long as there was any value other than the initial one, we knew it had been set. That was back in programming languages that didn't have easy ways to detect an undefined variable and when it was stressed to always declare variables rather than relying on the language to handle it (undefined values are treated differently with different languages). However, that logic only works if you are convinced that -1 will never be a legitimate value.
Here are some of the other places in the Community where the desire for negative points on a rubric have been brought up before.
Hi Michael - I tried adding negative values to criteria in the rubric, and while I was able to do it, I couldn't have a value lower than -1. If you are looking to deduct more than that, you could use the "I'll write free-form comments when assessing students" and the "use this rubric for assignment grading" options. That way, you could manually enter whatever score you want per criteria (+ or -) and Canvas would add everything and present it to your students!
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