How to Be a Teaching Assistant

by Jason Eisner (2010-)

This page is mainly directed at TAs and CAs for my classes. See also these excellent training slides from our department.

Thank you!

Thanks in advance for your work educating the next generation of students! You play an incredibly important role in the course. I still remember some of my TAs from my undergrad years.

"Learning has to occur in the students. You can do anything you like in the classroom or elsewhere—you can stand on your head—and it doesn't make a whit of difference unless it causes a change in behavior of your students. Learning takes place in the minds of students and nowhere else, and the effectiveness of teachers lies in what they can induce students to do."
—Herbert A. Simon, "What We Know About Learning" (1997)

General TA matters

There are lots of facets of being an effective TA/CA. At the start of term, we should discuss:

Each year we tend to make improvements to the class. At the start of term, we should discuss notes and todo items from the previous year, and decide who will be in charge of what initiatives.

Weekly discussion sessions (recitations)

Please emphasize discussion. If the students are just listening, they may not be learning. If you don't believe me, watch these videos.

These are not primarily homework help sessions. They are your chance to shine as a teacher and as a moderator of student-driven learning. Here are some things you can do:

The students should think of this as a small time investment. So please end after an hour: they should know that if they come at 5:30, you really are going to let them go at 6:30. Of course, if you wish, you can talk further to any interested students after the hour is over.

If you choose to solve past exam problems, here is one way to structure the hour. Hand out a printed copy of the questions (double-sided, stapled). For each question:

  1. Read the question aloud, or ask a student to read the question aloud.
  2. Ask if the question is clear.
  3. Have them discuss the answer in small groups.
  4. Ask for votes, or ask someone to explain their answer.
  5. If the class doesn't all agree on the correct answer, then you can have them discuss further, or you can try to clarify a difficult point.

You can cover the questions out of order if that seems useful. If you don't have time to cover all the questions, that's ok. At the end of the hour, hand out a printed copy of the answers, so students can review the official answers and can try any questions that you didn't have time to get to.

A simple review activity is to project some of the recent Powerpoint lecture slides (they are on the course webpage, although occasionally that version is slightly out of date). Flip through them slowly (at least 5 seconds per slide), and tell people to stop you when they see something they want to ask about.

Note: Try using a when2meet or Doodle or Piazza poll to pick the times—perhaps restrict to weekday evenings, or other ranges that the students say seem workable.

Feedback to students on assignments


Well before each due date, test the autograder thoroughly and send out submission instructions on Piazza. Students get stressed out if they don't know till the last minute what files to submit or how to test them.

If there is something wrong with a student's submission (e.g., some file is missing or doesn't run), email them as soon as possible to find out what is going on, and cc the staff list.

All assignments are due back to students by 1 week after the due date, or 1 week after submission in the case of a late assignment. This is incredibly important—I will be very unhappy if you let this slip. Schedule your other work accordingly, coordinating with other graders.

Why it's so important: Feedback is important for learning, but its value decays quickly as the students start to forget the details of the assignment. In fact, they are less likely to even read late feedback. Students also use the feedback to shape what they do on the next assignment. They would complain (legitimately) if they didn't get homeworks back promptly.


Please release the grades to students as soon as the assignment is fully graded. Ask them to contact you promptly with regrade requests if they have questions about your grading (this will simplify your life, and also gives the students extra incentive to read the feedback).

In fact, you may want to provisionally release grades before the assignment is fully graded. Don't let a few late students hold up feedback to everyone else, and don't let one late grader hold up feedback on all the other questions. You want people to be able to check comments as early as possible, while the problem is still fresh in their mind.

When you've graded all assignments (including late assignments), please send the class some statistics about the grades, so that they can realize that they're in trouble or feel proud of doing well. It is probably enough to send mean, standard deviation, and max, but sometimes I just send a sorted list of all scores (no names). You may be able to point them to statistics on Gradescope. You can also praise the class for doing well overall, and point out common misunderstandings.

Posting about the graded assignment also lets me know that the assignment is, in fact, graded. This would also be a good time to tell me how it went (see below).

If a student has not handed in the assignment (even late), please send them a personal email asking what's up. Ask them whether they have officially dropped the class, and cc me. Unless they have officially dropped, not handing in the assignment is a sign that they are screwing up one way or another. They need to hear this from an adult before it is too late to recover.

If a student has handed in the assignment but has used up their last late day in doing so, please send them a personal email warning them that they have no late days left for future use.

Specific feedback

Specific comments are expected. You'll be able to write longer, more explanatory comments if you reuse them across students. Comments about particular errors can be included in the grading rubric for easy reuse. Gradescope also allows reuse of free-form comments on a question.

Offer praise as well as criticism.

In cases where grading is more holistic (e.g., for a long and open-ended question or project), don't try to discuss every tiny bug. There is a limit to how much detailed feedback any student can mentally digest on one assignment. If there are many problems with the assignment, focus on the most important things. Give high-level advice, including "come see me to clear up these confusions."

It is sometimes appropriate to post on Piazza to debug common confusions.

Feedback to professor

After the assignment is graded, I'd like to hear how it went (in person or by email). What did students have trouble with? What were the most common comments that you put on the assignment? How should we improve or replace this assignment next year?

Please tell me about any assignments that suggest that a student might be having trouble and need extra help. We need to catch this early and get the student back on the track to success.

Please also tell me about any particularly strong or interesting assignments. Students deserve to have their professor know when they are doing neat stuff—they'd want me to know even if they never ask me for a recommendation. And from my side, seeing good work and creativity is one of the rewards of teaching.

If grading the assignment gives you any ideas for exam problems, please send them to me ASAP. Don't wait till it's time to write the exam.

Grading Rubrics

Often I have written my own solution to the homework. So please ask me to share my own answers, code, and output with you. Please also check your grading rubric with me.

A grading rubric might look something like this:

  10 points: Question 1

     3 points: Widget design
        -1 wrong number of prongs (but four-prong design ok if they explain flipping trick)
        -0 assume earth is perfectly spherical (no points off, but give comment)

     4 points: Widget implementation
        Give at least 1 point if the program compiles.
        Give at least 2 points if it gets correct output on all test cases.

        Syntax errors (limit to -2 total):
          -1 semicolon errors
          -2 curly brace errors
        Bugs (limit to -2 total):
          -1 inverted logic
          -1 skewed logic
          -1 rotated logic
        Poor practice (limit to -2 total):
          -1 no range checks
          -1 or -2 inadequate comments

     3 points: Analysis and discussion
        3 = great thoughtful discussion, almost perfect
        2 = good answer but misses a few points
        1 = only shallow understanding, or careless
        0 = badly confused or missing answer

As noted above, the rubric can also include suggested written comments for particular errors. As you grade, the rubric may grow with new errors and comments. Obviously, some changes may require that you revisit already-graded assignments to ensure consistency. Gradescope handles this automatically. If you aren't using Gradescope, then you should look at a sampling of student answers to design the rubric before you start assigning grades.

If a question has been used in a previous year, you can start with the previous rubric. However, don't assume that this rubric is a good one -- some are not! It's just a starting point. You may want to edit it or discuss it with me ...

Some fairness principles:

Gradescope settings when setting up an assignment:

Feel free to ask me for advice on any of this.

Regrade Requests

Students may sometimes complain about their grades. Gradescope makes it easy for them to submit regrade requests. We do want to fix clear grading errors, of course, especially systematic ones that affect multiple students or multiple problems for the same student.

A regrade request usually involves two questions: (1) Did the CA consistently apply the policy to this student? (2) Was it a fair policy?

The original grader is usually a good judge of question (1). If they made a careless grading error, they're normally happy to bring the grade into compliance. If the original grade was correct, they're normally happy to explain what the question was asking and why the student was wrong.

However, sometimes question (2) comes into play: the student is saying that our answer was wrong or our grading approach was unfair. The original grader may not be the best judge of this -- the head TA or the prof ought to weigh in. If the student has a point, then our response might be to fix everyone's grades.

To make sure we catch cases of question (2), a regrade request should be officially handled by a TA other than the original grader. The original grader should tell the TA how they plan to proceed. Often this is a simple plan and the TA will just say "go ahead." But in some cases, there might be some discussion, and the TA makes the final decision (consulting the prof if needed). This is also a chance to give useful feedback to the grader.

When there is a grading dispute that is not clearly on one side or the other, I usually just call a truce and promise to revisit it in the unlikely event that the final course grade is on the borderline. (This should be logged to make sure that we act on it at the end of the semester, and the prof can note it in the comments field at the right of the grading spreadsheet.)

Course Evaluations

At the end of the class (but before seeing their grade), students will have an opportunity to evaluate us along some important dimensions and provide other feedback. There will be a different separate report for each course number/section. We may have the opportunity to add course-specific questions. The general questions are as follows (as of 2020)::

  1. The overall quality of this course is: (poor, weak, satisfactory, good, excellent)
  2. The instructor's teaching effectiveness is: (poor, weak, satisfactory, good, excellent)
  3. The intellectual challenge of this course is: (poor, weak, satisfactory, good, excellent)
  4. The teaching assistant for this course is: (poor, weak, satisfactory, good, excellent)
  5. Please enter the name of the TA [or CA] you evaluated in question 4:
  6. Feedback on my work for this course is useful: (disagree strongly, disagree somewhat, neither agree nor disagree, agree somewhat, agree strongly)
  7. Compared to other Hopkins courses at this level, the workload for this course is: (much lighter, somewhat lighter, typical, somewhat heavier, much heavier)
  8. What are the best aspects of this course?
  9. What are the worst aspects of this course?
  10. What would most improve this class?
  11. What should prospective students know about htis course before enrolling? (You may comment on any aspect of this course such as assumed background, readings, grading systems, and so on.)

ABET Documentation

Every 5 years or so, for a few consecutive semesters, we have to collect samples of student work for ABET accreditation. For each assignment, quiz, and exam, the accreditors will need to see grading rubrics along with 9 graded samples of student work (3 excellent, 3 average, 3 poor). If we are in ABET mode (ask me!), you will need to collect and organize these materials throughout the semester.


It is obviously important to detect this. Discuss countermeasures with me in person.

This page online:
Jason Eisner - (suggestions welcome) Last Mod $Date: 2021/08/29 23:14:43 $