When You Don't Know the Answer

Being asked something you cannot answer is the worry new TAs mention most. It will happen, in office hours, in section, in lab and on the forum. The good news from every teaching center that writes about it: you are not expected to know everything. You are expected to be honest, to help the student find the answer, and to follow up. This page gives you the words, a way to debug code you have never seen, and when to hand a question to your instructor. Your instructor's rules for the course come first; where this page and your course differ, follow your course and ask.

Defaults that work. If you only take four things from this page:

Never bluff. "I don't know yet" costs you nothing. A confident wrong answer costs the student hours, and you have to undo it.
Always add a next step: "let's find out together", or "I'll post the answer by tonight".
Grades, deadlines, policy and unclear specs go to your instructor. Never guess on those.
When you got something wrong, correct it fast and where everyone can see it.

What to say

Say it plainly, then turn it into a plan

Any of these work. Pick the ones that sound like you:

"Good question. I don't know offhand. Let's look it up together."
"I'm not sure, and I don't want to guess. I'll check and post the answer on Piazza tonight."
"I'd have to check that. Can you show me where it comes up in the assignment?"
"That's a question for Professor ___. I'll ask, and we'll post the answer for everyone."

Students do not lose respect for a TA who says "I don't know." They lose it for a TA who bluffs and is wrong. A follow-up also shows how an expert finds answers, which is worth teaching.

Think out loud while you find it

If there is time, find the answer with the student: open the documentation, the assignment spec or the lecture slides, or run a quick experiment. Say what you are doing ("I'm checking the spec first, because that's what the autograder follows"). The student learns how to get unstuck without you, which is the real goal.

Close the loop

Before the student leaves, write down their name, the question and where you will answer. Answer within a day. If other students might have the same question, post the answer on the course forum instead of in a private reply, so everyone gets the same answer.

When you got it wrong

It happens to everyone. Correct it quickly, where the wrong answer was given: "Correction to what I said in section: the right answer is ___." Tell your instructor if it could affect grades. Fixing it fast builds trust.

Code you have never seen

Debugging a student's code live, with a line behind them, is the hardest version of not knowing. Research on TAs in office hours finds that the harder a TA finds the debugging, the less they use good tutoring habits. So keep the steps simple:

The student drives. Do not take the keyboard. "Walk me through what happens when you click Submit."
Ask what they expected. "What did you expect, what happened, and what have you tried?"
Find where expectation and reality split. "What should this line return? Print it and let's see."
Shrink the problem. A smaller input, a print statement, or one function on its own.
Time-box it. If it is not solved after about ten minutes and others are waiting, give the student the next experiment to run, help the next person, and come back.

Give hints from vague to specific ("look at your loop bounds" before "the loop should stop at n - 1"), and help only past the current roadblock. Once the bug is fixed, take one more minute for the idea underneath, or they will be back with the same bug next week.

On the forum

Do not post a guess. If you need to check, post "Checking with the instructor, will update this post," then edit the post when you know.
Your answer becomes part of the assignment. If a question shows the spec is unclear, send it to your instructor so the whole staff answers it once, the same way.
Read the other TAs' answers to the same question before you post, so students do not get two different answers.

When it goes to the instructor

Do not answer these yourself, even if you think you know:

Grades, regrades, extensions, late work and makeups.
Anything about academic integrity or AI use on a particular submission.
A spec that is ambiguous or seems wrong.
Accommodations.

The script: "That's Professor ___'s call. I'll ask and get back to you by ___." The Handle It or Hand It to the Instructor? page has the full list.

Shrink what you don't know

You can shrink the problem before office hours:

Do the assignment yourself before it goes out, or at least read the solution and run the starter code.
Ask the instructor and the other TAs where students got stuck last time.
Keep a short notes file of questions you could not answer and their answers. It turns into an FAQ by midterm.
Know who on staff knows what. "Let me grab ___, they know this library" is a fine answer.

If English is not your first language

Many TAs worry about this, and you are in good company. Some moves that help:

Check that you understood before you answer: "If I understand you correctly, you're asking whether ___." Most wrong answers come from answering a different question.
Ask the student to repeat, slow down or write the term down. Asking for clarification is normal in any language.
Write as you explain: code, a diagram or key words on the board or paper. It helps every student, not only you.
Treat hard questions as interest, not a challenge to your authority. Thank the student for asking.