Grading Explanations, Spring 2015

Go up to the CS 2150 page (md)

Participation grade

The participation was going to be based partially on the attendance taken, but there were a lot of problems with that. For some reason, the accuracy of the attendance records was not reliable. A number of students submitted support requests claiming that they were there; and for some of those, I could personally remember that they were present on that day. So while I could correct those issues, I did not feel that I could rely on the rest of the attendance sheets. So I ended up not being able to use them this semester.

Thus, everybody received a 100% on participation.

The number of Piazza contributions is also listed in the gradebook (don't worry about the 'max points' for that one -- I just had to enter something; the max points value for this entry is completely ignored). Like the attendance, this counts toward your participation grade. This important value is the number of contributions as reported by Piazza. This is mostly answers posted (among a few other factors), but does generally not include questions asked. Each contribution listed contributed 2 percent to your overall participation grade. While this may not seem like much, keep in mind that some students had dozens (or hundreds!) of contributions via Piazza. Note that the Piazza contributions only added to your participation grade.

This score was displayed out of 100, and rounded to two decimal places.

Grade parts

There were 11 full-length labs, and lab 12 had two parts. Lab 5 had the AVL tree worksheet, which counted as 4 more points. Thus, there were 35 lab parts (11 labs of 3 parts each, plus two parts of lab 12). So the total number of points for the labs was 35*10+4 = 354. Labs counted for 40% of the final course grade.

Each midterm counted for 15% of the final course grade, even though the total number of points on each midterm was different. The final counted for 25% of the final course grade. And participation counted for 5%.

The grade breakdown (how much each part counts for the final grade) is as listed on the course syllabus (md).

Grade curves

The stated curve on the exams (and one of the labs) is listed at the bottom of the CS 2150 page.

The total curve, so far, is the sum of these values: 1.5 + 1.5 + 1.25 = 4.25 points.

Rounding

Yes, we round grades. Note that round(x) = floor(x)+0.5. So we add 0.5 points to everybody's curve to take into account rounding. Note that this means rounding is already taken care of, so if you get an 89.9999999999999999999, it's still a B+, no matter how many times you ask - you don't get to round a second time (in reality, it was an 89.49).

Course curve

The curve so far is 4.25 from the exams, and 0.5 for rounding, for a final course curve of 4.75. We rounded that up to 6. Thus, everybody got 6 points added to their average (your average being what the gradebook reports).

Grade breakdown

As stated at the beginning of the semester, each 10-point "decade" is a separate letter grade range (60-70 is a D, 70-80 is a C, etc.). The exact ranges, taking into account the course curve mentioned above, are below. Note: the following table ALREADY includes the course curve! So you take your exact average from the gradebook and see where it lies on this table. And rounding has already been taken into account (see above), so you don't get to round a second time.

Minimum course average Letter grade
50.0 D-
57.0 D
61.0 D+
64.0 C-
67.0 C
71.0 C+
74.0 B-
77.0 B
81.0 B+
84.0 A-
87.0 A
98.0 A+

Note that the A+ range and the D- range follow a slightly different pattern. The A+ range is a percentage of the class (in this case, the top 6 course averages), and thus ended up being 98.0. The D- range extends down a bit more.

Permanent record

I've enabled the (terrible) Collab gradebook tool, and imported all the grades into there where they will live for all eternity. Or at least until UVa doesn't feel like keeping them around any more...

Lab regrade statistics

There were 7,547 lab parts that were graded: approximately 216 students times 12 labs time 3 parts (it's not exact because of people who dropped the course, but completed some of the early assignments, as well as non-submissions). There were 228 regrades submitted (3.02%). Of those, 83 were submitted because of extensions, leaving 145 remaining (1.92%). Of those, 61 had no grade change, leaving only 84 regrades (1.11%) where we messed up the first time around requiring a grade change. Last semester (fall 2014) we were at 2.03%, so we are getting better.