Questions to Ask a Postdoc Candidate
For principal investigators, and the lab members who sit on the panel, deciding which questions to ask a postdoc candidate. The questions follow the order the conversation usually takes: the PhD work and the candidate's own part in it, technical depth and troubleshooting, research ideas and fit with the grant, independence and writing, working with students and the team, then career plans, fellowships and start dates.
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The questions
Each question, and why to ask it
PhD work
Can you summarize your PhD research in a few minutes, for someone outside your subfield?
Why ask it
Nearly every candidate has a version of this ready, so it is a fair place to start. A strong answer opens with the question and why anyone should care, while a worrying one starts at chapter one and runs out of time in the methods. If students are on the panel, ask one of them afterward whether they could follow it.
What was the central question of your thesis, and what do you now think the answer is?
Why ask it
This separates someone who owns a question from someone who carried out a list of experiments. Listen for a plain statement of what is known now that was not known before, with its limits attached. If all you get is 'it's complicated', ask what result would settle it.
Which parts of your thesis work did you design and carry out yourself, and which came from your advisor or collaborators?
Why ask it
Papers from large groups hide who did what. A candidate who says 'I' for some parts and 'we' for others, and can name who did the rest, is giving you an accurate map. Credit claimed for everything needs a follow-up, and so does 'we' all the way through.
Pick one figure from your thesis or papers that you are proudest of. What did it take to get it?
Why ask it
The story behind a single figure is where hands-on work shows: the attempts that failed, the control added late, the weeks spent on one panel. Someone who cannot say how the data in their own figure were collected probably did not collect them. Choose a second figure yourself if the first answer is thin.
What is the biggest weakness in your thesis work, the one a tough reviewer would go for?
Why ask it
A candidate who names it faster than you could is the person you want reading the lab's drafts. 'I can't think of one' or a bristle is the worrying reply, because your own comments on their work will meet the same reaction. Follow with what experiment or analysis would close the gap.
Which project during your PhD did not work, and how long did you stay with it before changing course?
Why ask it
Every thesis has a project that never made it in. The timing is what to listen to: two weeks can mean giving up early, two years can mean nobody was willing to stop. Ask who made the call to drop it, since a postdoc on a fixed-length contract has to make that call without being told.
What is still unpublished from your PhD, and what is the plan for it?
Why ask it
Unfinished papers follow a new postdoc into the lab, and somebody's hours pay for them. Having one is normal and no mark against anyone. Ask for a realistic plan with a date, and agree before an offer how much of the first months it may take.
How did you and your advisor work together day to day: how often did you meet, and who chose the next experiment?
Why ask it
This tells you the supervision they are used to, whether that was a weekly meeting with a task list or a conversation twice a year. Someone moving from one extreme to the other can do well, but both of you should know it is a move. A long complaint about the advisor is a caution, and one calm sentence about what was hard is simply honest.
If you were starting the same PhD project again, what would you change in the first year?
Why ask it
Hindsight shows what they learned about planning research: run a pilot, choose a simpler system, talk to a statistician sooner. Those lessons are a large part of what a postdoc brings that a new student does not. 'Nothing' deserves a gentle second try, because it usually means the question caught them cold.
Technical depth
Which techniques could you run on your own in your first week here, and which have you only seen done?
Why ask it
A CV tends to list every method that appears in a paper with the candidate's name on it. Ask them to sort the list three ways: can do alone, have done with help, have watched. Honest sorting is a good sign in itself, and it lets you plan training around the truth.
Talk us through one of your main methods in enough detail that someone here could repeat it.
Why ask it
Give this one to whoever in the lab knows the method best, and let them ask the follow-ups. A person who has done it a hundred times mentions the fussy step, the thing they check before going on, the batch that behaved oddly. A fluent textbook account with none of that may be secondhand.
Tell us about an experiment or analysis that kept failing. How did you find out why?
Why ask it
Listen for the order of the search: one variable changed at a time, a return to a known positive control, a colleague asked. Repeating the same run and hoping is the worrying version, and so is switching to another approach without ever learning the cause. Ask what they would check first if it happened again.
For the key result in your main paper, what were the controls, and what would it have meant if one had failed?
Why ask it
Read the paper beforehand so you can name the result yourself. Anyone can list the controls from the methods section, but saying what each one rules out, and what a bad outcome would have done to the conclusion, takes understanding of the design. A candidate who inherited the experiment from someone else tends to slow down here.
How did you decide on sample sizes and statistical tests, and who checked the analysis?
Why ask it
The answer to hope for was settled before the data came in and can be explained in a sentence. 'It is what the lab always does' or 'the software default' means the choice was never theirs. For a theory, modeling or qualitative position, swap in how they check their own reasoning before showing it to anyone.
Has a result of yours ever failed to hold up when you or someone else repeated it? What did you do?
Why ask it
Ask it kindly, because the honest answer is uncomfortable. You want it told without flinching: what they checked, who they told and whether the record was corrected. If the answer is 'never', ask how often their results have been repeated at all.
How do you keep your notes, data and code so that someone else could pick the work up?
Why ask it
Have them describe what you would find if you opened a folder of theirs from a year ago. Dated notes, raw files kept apart from processed ones and code under version control are the things to hear. Their habits become the lab's problem on the day they leave, so if you have a standard, state it and watch the reaction.
Here is a result from our lab that we do not fully understand. What would you want to check first?
Why ask it
Bring a real figure or a real dataset, a puzzle and not a trick with a known answer. Watch the questions that come before any answer: how it was collected, what the control looked like, whether it was repeated. Do not mark anyone down for failing to solve in five minutes what the lab has not solved in a year.
The project needs at least one method you have not used before. How would you get yourself up to speed?
Why ask it
Name the method when you ask. A concrete reply has a person to shadow, a small pilot and a guess at how many weeks it would take. 'I learn fast' on its own is a claim, so ask for the last technique they picked up from scratch and how long it was before they trusted their own results.
Ideas and fit
What drew you to this lab in particular?
Why ask it
It shows whether they applied to you or to forty groups at once. The convincing version names a paper or an approach of yours and ties it to something they want to do next. A city they need to be in is an honest part of an answer, and when it is the whole answer, ask what in the science interests them.
Why do you want to do a postdoc, and why now?
Why ask it
A postdoc is a temporary position meant for training, so a good answer names what they need from those years: a second field, a method, papers aimed at a particular kind of job. 'It is the next step' is the reply to probe. Ask what they would do if no postdoc were on offer, and treat an honest look at industry as a point in their favor.
Which of our recent papers did you read most closely, and what would you have done differently?
Why ask it
The second half is the real question. A candidate who can offer a criticism politely to the authors' faces will be worth having in lab meeting, and if you hear only praise, ask which experiment they think is missing. Take the answer without defending the paper, since your reaction shows them how disagreement goes in your group.
Here are the aims of the grant that funds this position. Which would you want to take on, and what would you do first?
Why ask it
Send the aims ahead of time or describe them in two minutes. You have promised a funder this work, so you need someone who wants to do it and will not merely put up with it while chasing something else. Look for a first step that is specific and possible with what the lab already has.
With this position and a free hand, what would you want to work on in the first two years?
Why ask it
Nobody should be graded on a finished proposal here. A question, a reason it matters and a first experiment are enough. Then compare it with the grant: if the idea sits wholly outside what you are funded to do, say so in the room and see whether there is a version that serves both.
What would you bring to the lab that we do not have now?
Why ask it
A postdoc is often how a group gains a technique or a way of thinking. Look for something you could write down: a method, a model system, a kind of analysis, a working relationship with another group. Then ask what they would need from you to set it up, because equipment and bench space are your cost.
What do you want to learn here that you could not learn where you are?
Why ask it
The answer is a list of what you would owe them as a mentor, so be honest about what you can deliver. 'Nothing new, I want to keep doing what I do' suits a role that needs expert hands on a set task and is a poor fit for one meant to launch an independent career. Decide which of those you are hiring for before you judge it.
Where do you think this field is heading, and what is it getting wrong at the moment?
Why ask it
You are looking for a view held with reasons, whether or not you share it. Having no opinion after years in the area suggests narrow reading. This is a good one for lab members to push back on gently, since how a candidate defends a position shows more than the position does.
How much would the work you want to do here overlap with your PhD lab's, and have you talked with your advisor about it?
Why ask it
Who may keep using data, materials and unpublished ideas depends on the institutions and any agreements between them, so do not try to settle it in an interview. What you need to hear is that the conversation has happened or is planned. Someone about to defend may not have thought of it yet, so suggest they raise it before a start date is set.
Independence
If I were away for a month, how would you decide what to do each week?
Why ask it
A fair test for any PI who travels or runs a large group. The answer you want includes their own milestones and a clear point at which they would write to you anyway. 'I would wait until you were back' tells you how much supervision they need, and you have to decide whether you can give it.
Tell us about a time you disagreed with your advisor about the science. What happened?
Why ask it
The person to hire disagrees out loud, brings data, and then either persuades or is persuaded. Two versions should worry you: they never disagreed, or they disagreed and quietly went their own way. Ask who turned out to be right, because being able to say 'she was' without discomfort is a good sign.
Who wrote the first draft of your main paper, and how much did it change before submission?
Why ask it
'I wrote it and my advisor reworked the introduction' and 'my advisor wrote it from my figures' describe very different postdocs. Whichever you hear, ask for a writing sample. A thesis chapter written alone tells you more than a polished paper with six authors.
Have you written any part of a grant, fellowship or proposal? What became of it?
Why ask it
Applications that were turned down count: ask what the reviewers said and whether the candidate agrees, which shows how they take a rejection. No experience at all is common straight out of a PhD and should not count against anyone. Say how much proposal writing the position involves and see whether that is welcome.
How do you respond to a reviewer's comment that you think is wrong?
Why ask it
The mature answer separates wrong from unclear: if a reviewer misread the paper, the paper allowed it. Ask for a real comment and what the response letter ended up saying. A combative account is a preview of how your own notes on a draft will land.
When have you taken a project in a direction nobody asked you to?
Why ask it
This looks for initiative and then checks it: did anyone know? A side project that was mentioned early and given a time limit is what independence looks like in a lab, and one kept out of sight for six months is something else. Ask what it cost the main project.
At your busiest, how many projects were you carrying at once, and how did you decide which one got your week?
Why ask it
Tell them first what this position involves beyond the main project: a collaboration, a student's work, a paper in revision. A rule is what you want to hear, such as the one nearest a paper or the one other people were waiting on. Ask which project suffered, since 'none of them' is rarely true.
Suppose another group publishes your main result while you are still writing it up. What do you do that week?
Why ask it
If it has happened to them, ask for the real story in place of the hypothetical. The steady answer reads the other paper properly, works out what their own data still add, and brings the PI a choice between publishing fast and changing the angle. Panic is one worrying reply, and 'theirs must be wrong' before reading it is the other.
How do you know when a piece of work is complete enough to write up?
Why ask it
Some people polish forever and some send things out a control short, and a fixed-term position has little room for either. Ask about the last paper: which experiment was left out, and who decided. The reasoning matters more than which side they lean to.
Team
Tell us about a student you trained. What did they find hard, and what did you change?
Why ask it
Ask for one person, not students in general. The good replies describe the difficulty from the student's side and include something the candidate did differently because of it, while 'they were not motivated' is a warning about someone who will be at the bench with your students every day. For a candidate who has never supervised, ask who trained them well and what they would copy.
A student in the lab has an experiment that keeps failing and has stopped asking for help. What do you do?
Why ask it
Let a student on the panel ask this, since they are the one who would live with the answer. Notice whether the candidate goes to the student first or to you: either can be right, but the order shows instinct. Offering to run the experiment for the student sounds kind and teaches nothing.
What did you do for your last lab that was not part of your own project?
Why ask it
Looking after an instrument, running journal club, ordering, settling in newcomers: this is the work that keeps a group going. A blank may mean focus, or it may mean someone else always did it. List what postdocs carry in your lab and watch how the list is received.
Tell us about a collaboration that went badly. What was your own part in that?
Why ask it
Slow partners and mismatched expectations are common enough that nearly everyone has a story, so the second sentence is the test. An account in which the other side was wholly at fault tells you how a problem in your lab would be described later. Ask what they would agree in writing at the start next time.
Tell us about friction with someone in your own lab over shared equipment, bench space or credit. How was it settled?
Why ask it
Labs sour over small things: the instrument booked and left idle, reagents that vanish, a figure shown in someone else's talk. Going to the person directly and early is the reply to hope for, ahead of taking it to the advisor or letting it sit for a term. 'It has never happened' after years in a shared lab deserves a second ask.
How do you think authorship should be settled when several people contribute to a project?
Why ask it
Conventions differ between fields and even between groups in one department, so there is no single right answer. What you want is someone who would raise it early and in the open. Explain how your lab handles it and look for discomfort, because an authorship dispute is far easier to head off now than in the second year.
How do you like to be supervised, and what should I know about how you take criticism?
Why ask it
Set the first half against your real habits, since frequent check-ins and 'leave me alone until I have something' cannot both be met by one PI. A self-aware reply to the second half, such as 'I go quiet for a day and then come around', is worth more than 'I welcome feedback'. Describe your own style in return, because the interview is the cheapest place to find a mismatch.
What would the students and technicians in your current lab say about working alongside you?
Why ask it
It asks about the people with less standing on purpose, because an advisor sees a different side. If the candidate agrees, put the same question to a reference who worked beside them. Lab members who gave the tour or sat at lunch have firsthand evidence on this, so collect their view before you decide.
Plans and logistics
What do you want to be doing after this postdoc?
Why ask it
A faculty job, industry, a government lab, teaching and 'not sure yet' are all workable, and each calls for a differently planned postdoc. If a non-academic answer will not count against them, say so before they reply, or you will hear what they think a PI wants. 'I don't know' from someone just finishing a PhD is an honest answer.
What would you need to have finished by the end of this postdoc to get the job you want next?
Why ask it
This checks whether the plan has contents: papers, a technique, funding of their own, teaching experience. Set it beside what the position can realistically give in its funded length. If they need three years of independent work and the grant has half that left, the kind thing is to say so now.
Do you plan to apply for your own fellowship, and which ones have you looked at?
Why ask it
Each funder sets its own rules on who can apply and when, so ask them to check the terms and do the same yourself. A candidate who already knows the deadlines is planning ahead. Tell them what help the lab gives with applications, and find out from your own office what winning one would change about salary or the project, because institutions handle it differently.
Which part of the project would you hope to take with you when you set up on your own?
Why ask it
Easier to talk about before a start date than in the final year. It shows whether they are thinking toward independence, and it gives you the chance to say what you can let go and what stays with the lab. Having no answer yet is fine at a first interview, and you can skip the question for a candidate who is not aiming to run a group.
How long do you picture staying in a postdoc, and how does this position fit into that?
Why ask it
State the end date of the funding first, then ask. A person planning a short stop can still be the right hire for a contained project, but you need to know it when you scope the work. Keep to their plans for the job and leave partners and family out unless they bring them up.
When do you expect to defend, and when could you realistically start?
Why ask it
Defense dates slip, so ask what is left: chapters, a committee meeting, revisions on a paper. Whether someone can begin before the degree is formally awarded, and under what title or pay, is decided by the institution, so get that answer from your HR or postdoc office before you promise a date.
Is there anything we should start on now so your appointment paperwork is ready in time, such as work authorization?
Why ask it
What an interviewer may ask about immigration status, and in what words, depends on the country and on your institution's rules. Get the wording from HR or the international office beforehand, put it to every candidate the same way, and leave estimates of processing time to that office. Do not let it drift into nationality or family.
Are you talking with other labs, and is there a date you need to decide by?
Why ask it
The point is to avoid losing someone to a deadline you never knew about, not to gain leverage. A competing offer or a fellowship application that needs a host may mean they need your answer by a certain day. Say when you will decide, and then keep to it.
Besides your advisor, who knows your work best, and may we contact them?
Why ask it
An advisor's letter comes from someone with a stake in the outcome. A committee member, a collaborator or a senior postdoc from the same lab saw the daily work from another angle. Always get permission before calling anyone who is not listed, above all when the current advisor may not know the candidate is looking.
What would you like to ask us, and would you like time with the lab without me in the room?
Why ask it
A candidate's questions show what they are weighing: ones about the project, mentoring and where past postdocs went mean they are assessing you properly. Make the offer of time alone with the group sincerely, and do not ask the lab afterward what was said about you. If there are no questions, ask what would make them turn the position down.
How to interview a postdoc candidate
Practical guidance for the conversation itself
Before the interview
Decide what the position is
Some postdoc positions need expert hands on an aim the grant has already defined. Others are meant to grow someone into an independent scientist who leaves with a project of their own. Most sit between the two. Settle where yours sits before you meet anyone, because it changes which answers count: under Ideas and fit, 'I want to keep doing what I do' is a strength for the first kind of position and a concern for the second.
Read the work first
Read the candidate's main paper and the thesis abstract, and mark one figure and one result to ask about. Most of the questions under PhD work and Technical depth only bite when you can name the experiment yourself. If nobody in the lab can judge their main method, ask a colleague in a neighboring group to join for that part.
Share out the questions
On a panel, agree beforehand who asks what. The PI usually takes Ideas and fit and Plans and logistics. Whoever knows the candidate's method best takes Technical depth. Students and technicians take Team, since they will work beside this person daily, and anyone can take Independence. Without a plan the candidate summarizes the thesis four times and nobody asks about writing.
Find out what you may ask
Rules on interview questions about immigration status, age, health, family and similar matters differ by country and by employer. Before the first interview, ask HR or the postdoc office how it works at your institution: what may be asked about work authorization and in what words, whether someone can start before the degree is awarded, and what the lab can and cannot promise about salary. Then use the same wording with everyone.
Send the aims and plan around the talk
Give the candidate the funded aims, or a short description of the project, a few days ahead so the fit questions get a considered reply. If the visit includes a research talk, let the questions after it do the work of the PhD group, and spend the interview itself on the groups a talk cannot cover: Independence, Team and Plans and logistics.
In the room
Begin with their own work
The list opens with the PhD for a reason. It is the one subject on which the candidate knows more than the panel, and people think more clearly once they have been the expert for ten minutes. Leave the puzzle from your own lab and the questions about disagreement until after that.
Ask for the particular case
'How do you troubleshoot?' gets a philosophy. 'Which experiment kept failing, and what did you change on the third try?' gets what happened. Nearly every question on this page improves when you tie it to a named paper, figure, student or month.
Tell the truth about the job
Say when the funding ends, what shared duties postdocs carry, how often you are away and how long drafts wait on your desk. A good candidate is choosing between labs and will ask current members anyway. Hearing it from you first is what makes the rest of what you say believable.
Give the lab time without the PI
A coffee or a lunch with students and postdocs, with the PI elsewhere, lets the candidate ask what they would not ask you and lets the lab see how they treat junior people. Tell the lab beforehand that you will ask their view of the candidate and will not ask what was said about the group.
Leave time for their questions
Hold back at least ten minutes. The questions a candidate asks belong to the evidence, and a rushed 'anything for us?' at the door loses it. If time has run out, offer a short call the next day and keep the offer.
Weighing what you heard
Separate the person from the pedigree
A well-known PhD lab and a paper in a prominent journal tell you about the group the candidate came from. The questions about their own part, the controls and the first draft are there to find what the candidate did. Someone from a small group who designed, ran and wrote up a modest study alone may be the more independent scientist.
Write your view down before you compare
Ask each panel member to note a yes, no or unsure and two reasons before anyone speaks. Once the PI has given an opinion, students rarely contradict it, and theirs is the view you cannot get any other way.
Call the references with specific questions
Letters are written to help, so a short call adds what a letter leaves out. Ask which parts of the main paper were the candidate's own, how they respond to comments on a draft, how they were with students, and whether the referee would take them back. A pause before that last answer is worth noticing. Call only the people the candidate has agreed to, and ask HR whether your institution has rules on when references may be contacted.
Allow for language and nerves
Many candidates interview in a second language, on a video call, at an awkward hour. A slow sentence is not slow thinking. Put the lab puzzle on a shared figure or on paper and give a minute of silence to look at it, and judge the reasoning, not the fluency.
Judge against the stage they are at
Someone defending next month has usually not written a grant, run a budget or supervised a doctoral student, and those gaps are what the postdoc is for. Weigh what they did with the chances they had. The comparison that matters is with other people at the same stage, not with the postdoc who just left after five years.
Mistakes to avoid
Hiring the publication list
A long list can belong to a person who was one pair of hands among many. If the interview never establishes what the candidate designed, fixed and wrote, you have interviewed the papers. Go back to the first two groups before deciding.
Being vague about the funding
'There should be money for a third year' is a hope. Give the dates you can stand behind and say plainly what depends on a renewal or a fellowship. A postdoc who moves countries on a misunderstanding costs both of you far more than an awkward minute in the interview.
Drifting into personal questions
Partners, children, age, religion and where someone is from have no place in the interview, however friendly the lunch. If a candidate raises a partner's job search or a family move, answer what they ask and point them to whoever at the institution handles it. Keep your own questions on the work, the plans and the dates.
Letting the puzzle become a contest
The question about a result from your own lab is there to show how a person thinks. Three senior people firing objections at a nervous candidate shows only how they cope with being outnumbered. One person asks, the others listen.
Leaving the practical questions until after the offer
A defense date that has moved, a visa process nobody has started or an unfinished paper that needs two months can each push a start well past what the grant can absorb. Raise them in the interview, check the institutional side with your office, and put the agreed dates in writing with the offer.