There is a single proctoring and grading pool for M&I GTAs, which means you’ll be grading both 2211 and 2212 tests regardless of which class you’re TA’ing for. Head TAs don’t grade exams during the semester, but they do grade final exams. GTAs who are first year grad students don’t grade final exams (because you have your own finals to worry about!).
The M&I tests always have 4 free-response problems, usually multi-part, and occasionally some parts may be multiple choice.
The M&I Grading Rubric
The first time you grade, Greco will provide you with the Grading Rubric and walk you through the types of errors and penalties. As a quick summary, here are the four types of errors, along with a few examples:
- Clerical error. Examples: something that was correct but suddenly turned incorrect in the final result for no apparent reason; obvious calculator errors like using radians instead of degrees; missing units from a numerical answer; written units in a symbolic answer.
- Minor physics error. Examples: using sine instead of cosine of an angle when decomposing a vector into components; using the formula for moment of inertia of a point mass instead of the one for a solid sphere when calculating angular momentum.
- Major physics error. Examples: using conservation of energy in a problem that should have been solved with Newton’s second law; using Gauss’s law in a problem that needed Ampere’s law.
- Minimum progress. Example: it’s utterly wrong but there’s at least some kind of effort that demonstrates a slight bit of understanding, so the solution doesn’t quite deserve a zero.
The differences between the various types of error can sometimes be subjective, and sometimes it depends on what exactly the problem is asking for. For example, a missing minus sign could mean the student simply forgot to carry it over, making it a clerical error, or it could mean a fundamental misunderstanding of how to determine the direction of the magnetic field caused by an electric current, making it a major physics error. It is therefore extremely important for all graders to agree on what penalty to give for a specific error, to ensure consistency in grading.
Beware of Propagation of Error (POE)! An error in a problem should be penalized only once. For example: a student makes a mistake in part (a) of a problem, and they get it wrong. The result from part (a) is then used in part (b). The student has the procedure perfectly correct in part (b) but because they used their incorrect result from part (a), their answer for part (b) is wrong too. In this case, you take the points off from part (a) but award full credit in part (b). If you took points off for part (b) as well, you’d be penalizing the same error twice in the problem, which should not be done. Watching for POE is one of the hardest aspects of grading, so please make sure you pay close attention to it. There have been regrade requests in the past where upwards of 15 points were given back to a student because the GTA who graded the exam didn’t keep track of POE and penalized errors multiple times.
Grading M&I Exams
The M&I exams are graded electronically, through Gradescope. A day or two after each 2211 and 2212 exam, after all the exam papers have been scanned, all the GTAs will be informed that grading is now open, and Greco will provide you with a list of grading assignments on the M&I Slack channel — meaning, what specific problem and across which specific exams each person will need to grade.
The Head TAs are responsible for writing up the solution keys for the exams and sharing them with the GTAs (either through Office 365, or Slack, or both). When you first receive the test key, make sure to read through it. If you find any mistakes, or if there’s anything unclear, send a message to the Head TA in the M&I Slack channel. This way everyone will be aware of the error, and the Head TA will then correct it and send out a new key.
It’s possible that for the first grading session of the semester Greco will want to have all the GTAs together to start off the grading. Afterwards you’ll be able to grade by yourself. Keep an eye on the M&I Slack channel during the entire grading period and post if you have any doubts about how to grade anything in particular – for example, if you’re unclear on whether something is a minor or major error. Everyone should be doing this, and Greco and the Head TAs will answer your questions and resolve any conflicts.
2211 tests are Monday nights, and 2212 tests are Tuesday nights. Usually you have until the end of the week to complete your grading. Greco will give specific deadlines with each grading assignment (e.g., if you have to finish by Friday night, or Saturday night, etc).
How long does it take to grade exams? It depends. In the olden days, when all GTAs had to get together at the same time in the same room to grade paper exams, grading could last upwards of 9 hours, and you had to be prepared for a very long and tedious afternoon of grading. Thankfully, electronic grading is much more efficient. In the 2017-2018 academic year, the M&I exams were graded through Crowdmark, and each individual GTA would spend a total of 1-4 hours total on their grading. Starting in Fall 2018, grading happens through Gradescope instead, and the total time commitment turns out to be similar (roughly 4 hours max). Though of course, as you gain experience with grading, you’ll end up getting faster and spending less time grading.
How to use Gradescope
Please watch the video below.