Introduction

As we’re nearing the end of the quarter and I’m about to gather the data from our class forum (I’ve been using Piazza for the past four years in my classes), I was wondering how class participation has evolved between offerings of the same courses, or between different courses.

So here is all the (interesting) data I was able to collect.

Note that the statistics on Piazza have a specific format. When students ask a new question, that’s a post. When an instructor answers or when other students answer, that’s an answer. Now, on Piazza, there’s also the possibility to have follow-up discussions as part of each post. These discussions are not counted separately. Instead, Piazza reports a number of contributions which just includes everything (posts + answers + follow conversations).

Graphs

Contributions vs class size

The first thing I wanted to gauge was the Piazza activity per class. In order to compare apples with apples, let’s graph the number total contributions divided by the number of students for each class.

class_activity

Some interesting observations here:

  • ECS 36C - SQ19 was by far the most active class. The number of contributions per students is almost double the mean for all the other classes.
  • The activity for ECS 150 was higher in the first couple quarters (e.g., SQ17 and WQ18) and then stabilized itself for about 5 quarters. I’m guessing that after a couple offerings, and once the class contents became more stable, past students really started sharing their knowledge about the class with new students and there is a transmission of skills happening outside of the forum. My guess comes from the fact that the activity for ECS 150 surged again after we switched to online learning (FQ20, WQ21). Since students could not get knowledge from past students, since there is very little outside of class, in-person interactions anymore, the official class forum took a significant role again.
  • What is weird is that when ECS 36C switched to online last year (SQ20), the activity was the lowest observed for that class, compared to the previous, in-person offerings. I am guessing here that the switch to online learning was unsurprisingly confusing and painful.

Students vs staff

The second thing I wanted to measure was the activity of the staff (i.e., myself and sometimes the TAs) compared to the activity of the students.

group_activity

In some classes, where the contributions from students directly was very active and of very high quality, then the staff contribution could be as low as ~15% (e.g., ECS 36C - SQ19). In some other classes, especially new offerings of a class, the staff contribution could be as high as ~30% (e.g., ECS 150 - WQ17 or ECS 158 - FQ18).

On average, about 20% of all contributions in each class came directly from me. (My wife says I shouldn’t be on Piazza so much 8-|)

Posts vs answers

Next, let’s measure the number of answers per post. When a student asks a new question on Piazza, the question can be answer by other students (collaboratively) or by the instructor or both.

answers

As we can see, students are pretty active to answer other students’ questions. On average, almost 1.4 students collaborate to answer each new question.

Additionally, I (or TAs) also answer about 3/4 of all the questions on average.

Response time vs class size

Finally, let’s see the average response time, again versus the class size in order to fairly compare these numbers. Since the average class size is 200 students, the response time for each class was adjusted against that baseline.

response

As we can see, students can usually expect to receive an answer to their question within 8 minutes. In some classes, it’s been as low as 3 minutes! In some other classes, it’s been as high as 15 minutes…

Detailed data by course

You’ll find below the data I was able to collect from Piazza, and that was used to build the graphs above. If you play some more with the data and find interesting trends, please let me know!

ECS 30

  #students Total posts Staff responses Student responses Total contributions Prof contributions TAs contributions Avg response time
WQ18 393 936 534 1703 4718 793 50 4 min
SQ18 352 698 619 1062 3386 437 410 6 min

ECS 36C

  #students Total posts Staff responses Student responses Total contributions Prof contributions TAs contributions Avg response time
FQ18 179 674 539 1079 3746 701 190 5 min
SQ19 160 822 603 1373 4779 505 202 4 min
SQ20 155 373 311 387 1682 452 0 16 min

ECS 50

  #students Total posts Staff responses Student responses Total contributions Prof contributions TAs contributions Avg response time
FQ19 486 308 715 2490 462 6 6 min  

ECS 150

  #students Total posts Staff responses Student responses Total contributions Prof contributions TAs contributions Avg response time
WQ17 142 568 505 472 2444 526 252 21 min
SQ17 206 993 647 1266 4975 884 170 8 min
WQ18 201 848 631 1061 4321 765 220 6 min
SQ18 204 566 431 817 2826 491 200 8 min
WQ19 183 531 329 754 2632 534 9 8 min
SQ19 200 741 573 837 3288 452 336 9 min
FQ19 192 617 386 809 2903 603 42 11 min
WQ20 196 524 353 686 2246 468 0 15 min
FQ20 198 864 600 1297 4531 863 0 10 min
WQ21 196 746 531 1082 3849 788 0 10 min

ECS 158

  #students Total posts Staff responses Student responses Total contributions Prof contributions TAs contributions Avg response time
FQ18 51 119 82 105 440 140   16 min