How important is "research-fit" in post-doc hiring

Question

To clarify, this is my definition of "research-fit": research-fit is a term used in academia to describe the (degree of) overlap between research interests—and presumably also experience—of two or more individuals. It is commonly used in PhD admissions to match applicants to potential advisors.

I am wondering whether a similar analysis is done during post-doc hiring decisions. Of course, if an English PhD applied to a physics post-doc, the answer is somewhat trivial. However, consider the following hypothetical scenario:

A theoretical computer scientist decides that they want to study algebraic geometry and indeed, they have trained in algebraic geometry (perhaps through demonstrable coursework), but have published only in theoretical computer science with possibly a small overlap that an algebraic geometer might not care all that much about. Would, then, an absence of "research-fit", in particular the absence of relevant research experience in algebraic geometry, be a hurdle in said computer scientist's interest to pursue a post-doctoral position in mathematics despite adequate training? I am not thinking of computational algebra, but rather, pure mathematics.

More broadly, are there situations where faculty may be interested in (or even have need for) post-doctoral candidates from outside their field?

Answer 1

This depends entirely on the group one is joining. I've seen a situation where there were no expectations at all, other than the general subfield of math. But there are other situations where a post doc is hired for a specific purpose and the PI (say) is looking for an expert in that precise topic.

The first case I mentioned was more to see if a promising faculty candidate would fit into a department (he did, and was later hired as an assistant professor). But the short term of most post doc positions might indicate that some specific talent is needed in a specific project.

And, anything in between is also possible. Each position is distinct. Read the announcement for hints and ask people doing the hiring about "fit".

Most post docs, however, are expected to produce something. I think it rare that it is treated as a purely educational opportunity.

Answer 2

It depends on the job, the hiring panel, and the competition. I was once on a committee looking to hire a physical oceanographic modeller. It was difficult to find good candidates in that field at the time, so as well as interviewing a couple of physical oceanographers, we interviewed an applied mathematician with a strong programming background and a physical limnologist. In the end, we hired the mathematician. More recently, I was on a hiring committee looking for a marine ecologist with a particular skill set. We interviewed — and seriously considered — a terrestrial ecologist who had an impressive CV and had the skills we were looking for, but in the end, we took the safer bet of hiring someone who was already working in marine ecology. The stronger your CV, the more likely you are to be considered for a job outside your immediate research area. The harder it is to find good candidates in the field you are aiming for, the more likely it is that you will get a look-in. But if there is strong competition from people who have been working in exactly that area, you’re a long-shot.

Answer 3

Depends on where the money is coming from and what the demands are. Typically agencies or sponsors with strict timelines and deliverables necessitate a tighter overlap because we don't have time to get people up to speed.

Industrial money has strict deliverables, often with weekly meetings. The postdoc better be directly aligned and start producing ASAP. DoD/NASA with monthly meetings, there can be a bit of flexibility. DoE with quarterly, even more so. NSF doesn't really fund postdocs so no comment there. NIH (still trying to crack that nut). Foundation/fellowship money is the best because the postdoc is free to explore and learn, and typically just a short report is required annually. I just hired one of the latter and it was more fun looking for people who could bring a diversity of background to some of the projects I have going, without any strict pressure to produce right away. Whereas my current search for an industrially-funded postdoc is a bit of a headache as I need some very specific skills, and I need their start dates to align.

Answer 4

Research administrator here -- I work at an R1 and support PIs with various fields, but specifically Computer Science. I help with the appointment process for portfolios assigned to me, so I would like to mention some possible administrative hurdles based on my experience with a diverse group of people within the same institutional policies. Overall, I want to emphasize that there is a widening gap in the culture of hiring in CS from the rest of the engineering and applied sciences. Because of the competition with Big Tech, there are more options for postdocs, and they know them and use them to their advantage. Sometimes that is ok, but often I find many more obstacles with the appointment process because we are competing with industry to make competitive offers. I have not found there to be equal pressure in the other departments.

Need for Specific Expertise

As an example, we have cases where a materials engineer requires a computational person on their project, and they find it more useful to add such a person to their group rather than create a collaboration with someone else in another group/institution. Here are some questions I would raise for this scenario:

1. Are you paying this person the same as the rest of your lab? In this case, CS people make much more than materials postdocs. This can cause issues in the lab.
2. Is this person being appointed with the title of postdoc in CS or in Materials? Are there rules requiring one title over the other (e.g., based on their PhD field)?
3. What are the specific advantages of personally mentoring someone who does not have the same background as you? If they are on your grants and you are the PI -- you have to oversee their work. How will you do this if you do not know their field? Who will help them if you cannot?
4. Are there visa issues that prevent this from working out? There could be a problem for OPT paperwork if that is a factor and a different field is used in the appointment process.

I have seen this work out in cases like this, but the PI needs to be very engaged and work to find solutions for the obstacles that will inevitably arise. It's not an "easy" path.

Hoping for a Strong Postdoc in the Lab Regardless of 100% Fit

I have seen cases, particularly in CS, more than other fields, where postdocs appear to be looking for a temporary home and use the PI as a stepping stone. The PI also is hoping to get some help in the lab, and due to a shortage of postdocs, accept the individual. I never saw this happen ten years ago; it's now much more common, and something I am wary of. Once they are in the lab, I have seen postdocs actually refuse to work on their PI's grants and projects. As you can imagine, this is pretty upsetting for the PI. They felt like they had a strong person in their lab, but it turns out this individual was not interested in the PI's topic, and thus, it caused tension in the group. My questions in these cases:

1. How do we pay a person who doesn't want to work on the PI's projects?
2. How can the PI mentor someone where their research interests do not align?
3. Does the PI need to be able to go through a disciplinary process and are they prepared to do this if necessary?

In these cases, the postdoc often ends up leaving on bad terms. I do not advise this situation at all.

General Advice

Overall, you need to make sure offer letters are clear on what the topics will be that need to be worked on. Make sure that this will help if you need to go through a disciplinary procedure. Talk to your faculty affairs/appointing office prior to making offers. If the difference in field is large, ask about salary requirements. Check on visa requirements if that is a factor. Try to find additional support on the intellectual side so that you are not alone in mentoring this person.

Make sure you know about all of the possible hurdles with making an appointment and keeping the relationship stable before entering into a complicated appointment.