Thresholds in missed assignments predicting final grades

First, a note on a quick research project that yielded nothing interesting: I checked whether Canvas page views immediately before going remote, immediately after going remote, and the change in page views during that period were correlated with final grades, and they basically weren’t. I was wondering whether students who tended to check Canvas a lot (during the remote instruction period and before it) tended to do better in the class overall, and I didn’t find any evidence of that.

Also, and this will be mentioned again later, in checking the average scores for assignments over the past semester, I noticed that assignments that had to be done in a group were more likely to be completed than those that weren’t. This is interesting to me because setting up a Zoom meeting and talking to classmates, sometimes in other countries, would seem to be harder, not easier, than completing a worksheet by oneself. However, just taking two types of assignments from my Written Language class as examples, Reading Circles, which had to be done as a group via Zoom (or in person before we went remote in March), had a mean score of about 93% for the term, while Classwork, which included many assignments that were completed solo, had an average of 89%. In the Oral Language class, Discussion Circles (a sort of role-playing exercise with questions on an assigned topic) had an average scores of 99%, and Classwork 90%. It seems that Zoom meetings and the rare chance and synchronous interaction that they represent facilitate work, despite the pain of setting them up.

In other news, I have just completed my first academic year at the university IEP that I started at full-time last fall. As a celebration we got Thai takeout from one of the three good Thai restaurants in town (there are, mysteriously, no good Indian restaurants for 40 miles in any direction), and I immediately started blogging, vlogging, and tinkering with Google Sheets to fill the void left by work.

I’ve been slowly adding functionality to the Google Sheets that I use to do my end-of-course number crunching, mostly by figuring out new ways to use the FILTER function along with TTEST to see if there are statistically significant differences in my students’ final grades when they are separated into two populations according to some parameter. I put together a master Sheet for the year that included all of my classes between last August and now.

One possible factor that I had noticed anecdotally throughout the year was that students seemed more likely to fail or do poorly for assignments not turned in at all than for assignments done poorly. There was no shortage of work that was half-finished or ignored instructions, but the really low grades for the course were usually for students with work that was not even turned in.

So I set up a t-test on my Google Sheet to separate my students into two populations by the % of assignments that received a grade of 0 and look for a statistically significant difference in their final grades. Naturally, one expects students who have more 0s to do worse, but I still wondered where the dividing lines were – did getting 0s on more than 5% of assignments produce statistically significantly different populations? Did 10% do the trick? Is there a more graceful way of expressing this idea than “statistically significantly different”?

The relevant cells in my Google Sheet look like this:

As you can maybe figure out from the above, missing 10% of assignments (regardless of the points that those assignments were worth) produced a statistically significant difference in final grades: those who missed 10% or more of assignments had a final course grade of 66.9% (or D) on average while those who missed less than 10% had an average course grade of 90.8% (or A-).

On the other hand, getting full scores (which in my class means you followed all the directions and didn’t commit any obvious mistakes like failing to capitalize words at the starts of sentences) on more than 50% of assignments also produced a statistically significant difference in final grades: those who got full scores on 50% or more of assignments had a final course grade of 93.2% (or A) on average while those who got full scores on less than 50% had an average course grade of 78.4% (or C+). This isn’t the difference between passing and failing, but the ratio of full scores does produce two populations, one of which fails on average and one of which passes – see below.

Other significant dividing lines were:

  • Missing 3% of assignments
    • If you missed more than 3%, your average grade was 83.3% (B)
    • If you missed 3% or less, your average grade was 92.1% (A-)
  • Missing 5% of assignments
    • If you missed more than 5%, your average grade was 78.6% (C+)
    • If you missed 5% or less, your average grade was 91.7% (A-)
  • Getting full scores on 35% of assignments
    • If you got a full score on more than 35%, your average grade was 90.0% (A-)
    • If you got a full score on 35% or less, your average grade was 68.0% (D+)
  • Getting full scores on 70% of assignments
    • If you got a full score on more than 70%, your average grade was 96.6% (A)
    • If you got a full score on 70% or less, your average grade was 85.0% (B)

As you can see, I am not a prescriptivist on the use of the word “less”.

As you can also see, there are some red lines that pertain to the number of assignments that students can miss before they fall into a statistical danger zone: 10% of assignments missed, or only 35% of assignments with full scores. A student who fails to meet these thresholds is statistically likely to fail.

Statistics like these don’t carry obvious prescriptions about what to do next, but I worry a bit that the number of missed assignments will go up as classes are moved permanently online and assignments lose the additional bit of salience that comes from being on a physical piece of paper that is handed to you by a physical person. I also, for mostly bureaucratic reasons, worry that my grades seem to reflect less “achieving learning outcomes” and more “remembering to check Canvas” – although I’m sure this discrepancy is nearly universal in college classes.

I am considering giving fewer assignments per week that are more involved – fewer “read this article and complete this worksheet” and more “read this article, make a zoom discussion, and share the video and a reflection afterward”. We will see if that produces grades that reflect the quality of work rather than the mere existence of it.

2 thoughts on “Thresholds in missed assignments predicting final grades

  1. This is good! Thanks for sharing your research. I’m wondering if you will show this to your students in the beginning of a new semester to show them what they do to to successfully complete the class with 70% or mor, with 80% or more, and even with 90% or more. Also, would you mind sharing the discussion circles?

    Liked by 1 person

    1. Thanks. I wonder if I should build this into my first-day PPT. I do tell them that not checking Canvas is a reliable way to fail.
      As for the discussion circles sheets, see the post after this one.

      Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s