Sum of Grades Aggregation Putting Zeros for Blanks

Sum of Grades Aggregation Putting Zeros for Blanks

by Greg Dietrich -
Number of replies: 12

I can't figure this out...we don't want blanks counted in the calculation of the grade. In the example I have here there are a total of 8 assignments in the category. One assignment is worth 5 points, the other 7 are worth 100 points. When we put 5 points in for the first assignment, it gives the overall grade as .71%. How do I make this not put zeros in for blanks? This only happens with Sum of Grades as well...it doesn't happen with Weighted Grades.

Under Admin-->Grades-->General Category Settings I have "Aggregate only non-empty grades" set to "Yes." I have some screenshots attaches as well if it helps.

In reply to Greg Dietrich

Re: Sum of Grades Aggregation Putting Zeros for Blanks

by Emma Richardson -
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So I am presuming that Sum of Grades is really Simple Weighted Mean of Grades but that someone has changed the language.  Is it possible that the calculation has been changed for this as well?  

In reply to Emma Richardson

Re: Sum of Grades Aggregation Putting Zeros for Blanks

by Greg Dietrich -

Sum of grades is a different aggregation than simple weighted means of grades. I'm fairly confident that I have the calculation correct, as you can observe in my screen shots. I'm pretty certain this is a case of blanks being treated as zeros.

In reply to Greg Dietrich

Re: Sum of Grades Aggregation Putting Zeros for Blanks

by Emma Richardson -
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If you switch to simple weighted mean - does that score correctly?  It acts just like total points.  I don't use Sum of Grades so I am wondering if there is something in that calculation that excludes the option of ignoring blank grades.  I think you are right because the resulting score is exactly what it would be with your blanks being counted as zeros.

In reply to Emma Richardson

Re: Sum of Grades Aggregation Putting Zeros for Blanks

by Greg Dietrich -

OK, looks like this method works and accomplishes the same result we are looking for. We didn't have the simple method even enabled on our site so no one would of thought to look for it. We do now though! I think I just might turn off Sum of Grades as well...

In reply to Greg Dietrich

Re: Sum of Grades Aggregation Putting Zeros for Blanks

by Emma Richardson -
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Yes, I have shut off everything except simple weighted and weighted.  Been working well so far.

In reply to Greg Dietrich

Re: Sum of Grades Aggregation Putting Zeros for Blanks

by Lisa Foster -

Sum of grades does count the empty cells as zeros.  I switched to simple weighted grades and it is working.

In reply to Greg Dietrich

Re: Sum of Grades Aggregation Putting Zeros for Blanks

by Bob Puffer -

Even though it looks like you can "Aggregate only non-empty grades" in "Sum of grades" agg method, the method ignores it.  A colleague has recently come up with a workaround, mark all your ungraded items Extra credit and they will not be counted until you grade them and unmark them for Extra credit.

In reply to Bob Puffer

Re: Sum of Grades Aggregation Putting Zeros for Blanks

by Greg Dietrich -

Thanks...good work around that works. Too bad we have to have "work arounds."

In reply to Greg Dietrich

Re: Sum of Grades Aggregation Putting Zeros for Blanks

by Bob Puffer -

Maybe this is a good time to ask about the use-case for sum of grades.  It would seem to me that simple weighted accomplishes the same thing as long as everything is in the same category and provides you with the ability to only count graded items.  Maybe the thing I'm missing is that we use the LAE Grader report which automatically tallys point correctly and Moodle's core uses the "real" value (which couldn't be more mis-named) which is only another version of percentage.

In reply to Bob Puffer

Re: Sum of Grades Aggregation Putting Zeros for Blanks

by Vicke Denniston -
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Thank you for the workaround, we are at the point of the term where this has become a hot topic. I have to agree with the idea that it's a shame there has to be workaround, and the general opinion that it doesn't work as it should is "that's stupid, so look it up somewhere else"