By Dr. Breah LaSarre

If you are reading this blog post, you have likely decided that you want to get additional training after graduate school by working as a postdoctoral researcher (i.e., postdoc). A postdoc position is a great opportunity to hone and expand your research skills while gaining mentoring and teaching experience. All of these skills are indispensable if you want to lead an independent research group, be it in or outside of an academic setting. However, to make the most of this opportunity, you need to find a postdoc lab that is a “good fit” for you. This will involve weighing some obvious factors, including the general research topic, the lab location, the skills and expertise that you can bring to the lab, and the new skills and expertise that you can acquire from the lab. However, a less obvious aspect that many postdoc candidates find themselves considering is the seniority of the lab’s principle investigator (PI) – that is, whether it is better to join the lab of a newer, junior PI or that of a more senior, well-established PI. This blog post discusses some, but certainly not all, elements to consider regarding PI seniority when searching for a postdoctoral appointment and how to determine the best postdoctoral advisor for you.

Like graduate students, postdocs perform research under the supervision and mentorship of a PI. Unlike graduate students, postdocs are expected to take primary responsibility for the design, the execution, and the publication of their research and, thus, depend less on their PIs on a day-to-day basis. However, PIs play a critical role in helping postdocs develop professionally both in and outside of the lab. Without the support and assistance of your postdoctoral advisor, you will have a very difficult time getting your own funding or publishing papers; moreover, you will likely have fewer opportunities to present your work at conferences, mentor junior researchers, develop a teaching portfolio, or acquire other experience that would better position you for an independent research career. Thus, choosing the right postdoctoral advisor is crucial if you want to get the most out of your time as a postdoc.

I have been asked several times if I think junior PIs or senior PIs make better postdoctoral advisors. In my opinion, the answer is not black and white. Regardless of seniority, all PIs are individuals with their own strengths and weaknesses that will influence both how they approach scientific research and how they mentor and train their lab personnel. Just as you have been evolving as a scientist since you started graduate school, PIs evolve too, not just as scientists but as lab managers, mentors, teachers, and colleagues. Most PIs improve at various aspects of the job as they gain experience. However, PIs can also develop habits over time that don’t serve trainees well. Additionally, as they move farther away from their own postdocs, PIs may be less in tune with your needs or less empathetic to your situation.

That being said, there do exist some seniority-related trends that I am aware of, either from my own experience or from conversations with other postdocs. I have done my best to summarize them here.

Junior PIs

One potential benefit of working with junior faculty is that, because they are just starting their labs, their success is inherently tied to yours. Junior PIs have a strong need to publish quickly and consistently in order to obtain funding and secure tenure; they can’t do it alone, which means that they need their lab personnel – in other words, you – to publish and be successful. Mutually assured success is great motivation for a junior PI to invest substantial time and effort in your postdoctoral training and development. Being a postdoc in a new lab can also present advantages in the quality of training you will get. Junior PIs are much more likely to train you themselves, as their labs are smaller and are likely to have fewer or no other postdocs or permanent scientists who can train you. Being the only postdoc in a lab, or one of only a few, can also position you to be the PI’s “right-hand man or woman” and gain more mentoring, administrative, grant writing, and managerial experience than you might gain in a larger, more established lab. Finally, you are also more likely to initiate the founding avenues of research for the lab, rather than picking up a project where someone else left off.

On the flipside, there is one risk that people invariably think of when it comes to joining a newer lab: A junior PI could fail to get tenure. This is a big risk that is not easily assessed, as junior PIs have yet to prove themselves in various ways. These “unknowns” can strongly impact your success as a postdoc. First, junior PIs have limited or nonexistent track records when it comes to acquiring funding and publishing, so there is less certainty that your research will be funded for the duration of your postdoc or that you will successfully publish your work. Second, as junior PIs are new to running their own research groups, they are still developing their own mentoring and management styles. They are also less likely to have experience mentoring postdocs. Consequently, you cannot be sure whether a junior PI will be a good advisor. Third, although the generally small size of a newer lab can mean that you will get more attention from the PI, it may also mean that you have to train new lab members and may not be in a situation to learn from your labmates. Being the only postdoc also means that you won’t have a built-in cohort with whom to socialize or navigate the various hurdles that you’ll encounter as a postdoc. Fourth, junior PIs are early on in the process of making names for themselves and forming connections with other scientists; thus, a junior PI might not be able to provide helpful name recognition or connections to pertinent individuals when it comes time for you to present at conferences or go on the job market. Finally, depending on how new the lab is, a substantial amount of your time may need to be spent getting the lab up and running and developing new protocols and systems, which may delay progress in your own research. Overall, you have to have a bit of blind faith in the capabilities and future success of the PI to join a newer lab.

Senior PIs

The benefits of working with a senior PI are likely more obvious than those associated with a junior PI. Generally, senior PIs have extensive experience acquiring funding, publishing papers, and mentoring, all of which can be beneficial to your postdoctoral trajectory. Senior PIs often have a good grasp of the big picture and can more clearly envision how things will play out, both experimentally and in your career. Senior PIs may also have more grant money and other resources than junior PIs, which may enable you to do a larger number of experiments or pursue expensive, cutting-edge experiments. Large grants may also allow the PI to hire individuals such as technicians and lab managers to handle the administrative needs and rudimentary tasks in the lab, allowing you to spend more time on research. Separately, senior PIs tend to be well-connected within the scientific community, and these connections may help you secure a tenure-track position or other appointment. An association or recommendation from an established and well-respected senior PI is also likely to carry more weight than a recommendation from an unknown junior PI when you apply for training grants or jobs.

However, the potential benefits associated with senior PIs, namely, tenure, name recognition, and a history of training successful scientists and getting grants, can also give rise to a downside: The long-term success of a senior PI is not inherently tied to the success of every individual lab member. More specifically, the failure of a single postdoc in the lab of a senior PI is unlikely to hurt the PIs prestige or impede the ability of the PI to get future grants. Consequently, a senior PI may be less invested in you as a postdoc and may prioritize their own needs or the needs of other lab members over your needs. This can manifest itself in several ways. Senior PIs generally do not need to publish as quickly, so they may not prioritize getting your research out the door. Senior PIs also tend to engage in more activities outside of the lab, be it administrative duties, giving seminars at other universities, or sitting on grant panels. As a result, you may have less interaction with the PI on a day-to-day basis, especially if you are competing with a large number of labmates for your PI’s attention. Finally, although a senior PI may be well-connected, the PI may not fully leverage those connections on your behalf, either because the PI doesn’t recognize the importance of doing so or because the PI chooses not to. I want to emphasize that I am not saying that senior PIs are indifferent regarding the success of their postdocs, just as I am not saying that all junior PIs will fail to get tenure. Just recognize that a failing postdoc will almost certainly have a smaller impact on a senior PI’s career than on a junior PI’s career.

Final thoughts

Ultimately, the seniority of a PI does not directly correlate with the PI’s competence as a postdoctoral advisor. There are PIs at all levels that fail to effectively mentor their postdocs for one reason or another, and there are also many PIs, both junior and senior, that are great postdoctoral advisors. One generalization that could be made is that a senior PI offers more stability and certainty, whereas working for a junior PI is a higher-risk, higher-reward situation. Some postdoc candidates will feel that the level of personalized attention and the opportunity to shape the lab’s trajectory outweigh the unknowns associated with a junior PI, and they will be willing to take the risk. Other postdoc candidates will want to be part of a bigger group where they can do their research using abundant funds and equipment and without the extra pressure of needing to help the lab succeed. There is no right or wrong choice, and a lab that is a good fit for one person can be a terrible fit for someone else. It is entirely up to you what you are comfortable with and where you feel that you can most succeed. Additionally, you may find a way to get the best of both worlds. For example, if you decide to be a postdoc with a junior PI, initiate a conversation with your advisor about finding a senior PI to serve as your co-advisor, which could help offset some of the downsides associated with working with a junior PI. Alternatively, if you work with a senior PI, actively network and try to collaborate with junior PIs who are eager to help you move joint research projects along.

On a final note, whether you work with a junior or senior PI that excels or struggles with mentoring, your success as a postdoc depends largely on you. Yes, postdoctoral advisors need to provide ample support so that their postdocs can develop professionally, but postdocs need to take substantial responsibility for their own development and make sure that they use their time as a postdoc effectively. This includes taking advantage of available opportunities, seeking out additional opportunities as necessary, and communicating your needs to your PI. Overall, rather than focusing on PI seniority, you are encouraged to look for well-rounded scientists who value and respect your career goals as potential postdoctoral advisors.

Breah LaSarre holds a doctoral degree from the University of Illinois at Chicago. She has done research in microbial physiology and is currently a freelance scientific editor.

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