Marking from a TA’s perspective

It has been a VERY long time since I’ve posted about chemistry, I was an undergrad at that point, but I wanted to write something longer and more easily linked to then a twitter thread. I’m about to finish my Ph. D. and while I’ve done a lot less marking then many students, I’ve done enough to have a few opinions I thought professors might find useful. This is mostly based on my most recent experience, since it is fresh in my mind. Also, the list is not in any particular order after the first few big ones.

First: Don’t split marking up by student. This WILL lead to uneven marking as there is always stuff that needs a judgment call, and with one student I can remember “I’ve seen this way of answering the question before, what did I do there”. Now, you can do careful coordination and this semester I’ve tried to do that, but it makes marking take a lot longer and will never be as good. I’ve spent a lot of time describing my marking decisions, but I still get emails from students going “I lost a mark for this, and my friend didn’t.” Instead, split marking up by assignment or question. That way if one TA is a much harder marker then the other, every student gets the hard TA and easy TA equally.

Second: Don’t have big tables of balanced equations. They are the WORST to mark. So you’ve got a table of five equations, each with two reagents and two products. That is just five things to mark, right? No, you have to check that each of those products and reagents are correct, and have the right numbers of atoms. Then each of those products and reagents has a coefficient. So for something like “2 Al + 3 Cl2 Ž→ 2 AlCl3 (s)” I have to check three coefficents, two subscripts and three compounds. So for a table of five of these type of equations I have to check 5*3*2*3= 90 things for one table. At a certain point my eyes start glazing over and I worry I’ll miss mistakes.

Third: Don’t include things on the assignment that aren’t marked. I’ve had one assignment that had a page that wasn’t marked. That felt bad as some students (probably those who were running out of time) did that page and not marked worked. Boom, none of that work helped their grade.

Fourth: Make sure the question you are asking is what you think you are asking. Students will often answer very literally, so something like “What do you see in this part of the online interactive” will get a literal description, when what the professor wanted was just a description of the motion of the ions. Likewise, make the scope of your questions clear “Which ion is never soluble” is bad. “Which ion is not soluble in question three. is good. Also, check your answers. I had one case where there was a correct answer the prof didn’t realize since they’d accidentally not given an example where that ion was soluble. It isn’t a particularly insoluble ion, they just never showed it.

Fifth: Don’t worry about making the assignment total some round number of marks. I have had one prof who made every assignment total 10 marks. This leads to a lot of questions worth half a mark and other such annoyances. Your TA can normalize a grade at the end. Having to say 0.25/0.5 is more of a pain and more confusing to the student then 0.5/1.

Sixth: Don’t make us use annoying grades. Example: Make sure tables have a number of marked boxes that divide into a non-repeating fraction. I don’t want to have to write 1.33333… marks out of 2, and 1 1/3rd marks out of 2 is just confusing. But 1.5/2 is not.

Seventh: Don’t make students marge audio on a presentation when doing things online. I had to mark some oral presentations, and the first one with solo students was fine(tm). I mean, the recording quality was all over the place, but it was bearable, and you never know what sort of technology the student has access to, the lack of a quite space to record, whatever. HOWEVER, as soon as the prof assigned a GROUP project? BAD. The audio quality was often so bad that I got headaches trying to parse what the students were saying. I hurt my ears SO many times when I had to crank my speakers up for the first student, then the second student was super loud.

Eight: Make sure you aren’t assigning the students the same questions over and over. In one course I TAed I the students have a weekly LON-CAPPA problemset written by the university. These are generally very well written, and have been upgraded and tweaked over the years. Then they would get a Sapling problem set, which would redo the same concepts and similar questions, but with a worse input method, ambiguous wordings, and shinier graphics. Then they’d get a tutorial handout that some weeks would basically then duplicate the Sapling work. You could just pick one of these and you’d teach the same amount.

Nine: Make sure you aren’t just asking the students to copy stuff out of the online interactive. There was at least one set of questions that literally ZERO students out of the 80 I was marking got wrong. Then I realized that the question was to write out the equation for some reactions you saw in an online interactive. Except that the interactive showed you the equation below the video. So they were all just literally copy and pasting them in. Which means they were not learning anything, you weren’t marking anything except the ability to notice that equation, and all you are doing is generating marking work for the TA.

Ten: Make sure your marking schemes make sense. For example, A question with four checkboxes, and a note that it is worth two marks, but -1 mark per wrong answer. But no details on what is a wrong answer. If they check “add heat” instead of “remove head” is that one wrong answer or two? The TAs got permission from the prof to just assign each box 0.5 marks, and if that box was marked or not marked correctly they got the marks for it.

Eleven: Make sure your sig figs are consistent if you are going to mark them. There was one question where it was ambiguous if some of the numbers we gave them were infinite precision values or should be taken as a number of sig figs. Therefore, if you are going to do this, be clear. Don’t say 300 mL. Say either 300. mL (the notation our sig fig handouts specifies, but that I haven’t seen since undergrad), 300.0 mL (now is explicit) or 301 mL (technically still ambiguous but no longer has students thinking there is only one digit) or 3.00*10^2 mL.

Published in: on April 23, 2021 at 10:28 am  Leave a Comment  
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