aka The Life Cycle of a PI aka The Five Types of Profs You Might Work For
Labour day is around the corner, and so is the start of the school year. To help those looking to join a research group I’ve put together a list of the major phases in most professors’ career.
First, a couple of qualifiers. The most important thing when looking for a potential supervisor is their personality. If you get along with a person (and love their research) you’ll likely do very well in their lab, all other factors being equal. That said, when looking for supervisors at the graduate and postdoctoral level I only considered labs that fit the following equation:
Number of papers per year / Number of students ≥ 0.75
That is, for every student in the lab the PI should publish at least 0.75 papers per year (preferably >1, maintained over the last 5 years). This is a high bar, but goes a long way to taking the luck out of a scientific career . Publications are the currency of academia, and regardless of the quality of the lab an extended period of no publications will make it difficult for you to get scholarships, fellowships and grants [1, 2] .
1. The New Hire
Often mistaken for postdocs (or grad students), newly minted assistant professors are a high-risk, high-reward option. At least a plurality of the department believes their research ideas are red hot (otherwise someone else would have the job), but a new professor has no proven track record of independent research or lab management, and their chief source of funding is an ever diminishing start-up grant.
This is the one period where the interests of professor and student are perfectly aligned. New profs live or die by the research output of their students, and so they provide excellent one-on-one training. The first few hires in the lab (graduate or undergrad) will be ideally placed to gain many useful skills, and will reap the lion’s share of the early pubilcations. While a letter of reference from a junior faculty member may not carry as much weight as a professor near retirement, they are also much more likely to be effusive in their praise, and (provided the lab is successful), students will have a solid publication record to stand by.
For postdocs the view is less rosy. Close to the New Hire in experience, a postdoc gains far less from their intensive supervision. Recently postdocs themselves, new professors are also weak in many of the skills that postdocs lack (grant writing, lab management), and so can offer little in the way of training. Worse, the junior professor is just starting out in their independent career, and needs to show a strong ability to create original research. They may be less willing to share credit, and have not built up an extensive network of collaborators.
After 4-6 years a prof can no longer be called a new hire, and working in their lab will be an entirely different experience. Startup funding has given way to early career grants, and the PI has a solid reputation for work in their particular field.. At this point official promotion from assistant to associate professor is either a foregone conclusion or has already happened (otherwise stay far, far away).
In the lab, the first hires are in the process of writing and defending their theses (if they are on track for an 8-year PhD that’s another red flag), and those red-hot ideas that got the professor hired are coming to a close.
The most important factor for the success of an incoming student will be the next round of ideas. Outside of the Ivy league, years 5-10 will be a period of growth for the lab, as initial successes lead to increased funding. It’s a good time to arrive, provided that there are some good ideas to soak up all this new funding  . Look for vision, and a clear idea of how the initial works are going to advance. A philosophy of “more of the same, but bigger” can lead to diminishing returns, but with steady funding good profs can strike out into more ambitious territory, with a corresponding boost in impact.
3. Stability Sam
By mid-career an academic has survived both the tenure process and at least one bitter departmental feud. Outside of the odd move, labs that reach this point often exist in a stable equilibrium for a decade or more, old students graduating and being replaced by the same people with different faces. The PI is unlikely to take that fateful trip to Stockholm, but they are well respected in their field, with a dense network of collaborations.
The quality of a mid-career lab can usually be determined from the publication to student ratio, normalized over the last five years or so. Provided the lab culture is good, most labs in this phase will be good to join, especially as a graduate student. One caveat: in this period the burden of ingenuity starts shifting to the student, especially in the experimental details. Time away from the fumehood can translate into a dulling of chemical intuition, and it’s during this period that input from the experienced members of the lab (graduate students or postdocs) becomes important.
4. The Bigwig (Chair, Director, VP Research, etc.)
Broadly speaking, two types of people head into administration: those who have lost much of the original fire that drove them to research, and those with so much fire that one lab is not capable of creating all the change they seek  .
Regardless of motivation, administration draws much of these academics’ time, and their research often suffers. If their labs remain productive through the administrative term (and even absent oversight momentum will carry a good publication rate for ~3 years), it is likely that there is a strong guiding hand or culture at the lab level, often either from senior graduate students, postdocs, or research associates. As always, talk to peoiple in the lab—and take the pessimistic ones reports with a grain of salt—and get a feel for the lay of the land.
In the event of an absent PI the lab may still be an excellent fit , especially for those with prior training and strong, self-directed work ethic. The chair has first pick of departmental resources, and a good letter of recommendation can carry a lot of weight, especially if they have a history of great research.
5. The Greyhair
Not yet emeritus, these form the old guard in many departments. Those still actively involved in research are adept at departmental politics (expect them to have the nicest offices), and have established a nice, productive routine.
In the lab this may translate into an incredible depth of knowledge, a walking treasure trove of reactions and papers stretching back to the ’60’s. This is excellent for problem solving, but can lead to research calcification. After all, what use are new methods or approaches when the old strategies work just as well? (Especially if the lab has previously developed their own solution.)
Success in this environment depends on working at the edge of the lab’s expertise, either on projects with little history or by completely in the wilderness. With subjects the PI is less comfortable in their wealth of understanding can lead to new insights, and the high impact publications that result. This of course forces you to become an expert in something slightly outside the lab’s speciality, which is great for future job prospects but can be demanding and time intensive without a proper background.
 Beware large labs especially. With 20+ people they will ALWAYS be publishing great work, but this is true even if only 30% of the students are productive.
 My favourite counterexample is the double-Nobel prizewinner Frederick Sanger. He published at a rate of 2-5 papers per year for his whole career, and did most of the work either himself or with the aid of a handful of technicians. A graduate student in that lab may not publish much, but they’d get incredible training.
 Beware a high concentration of papers with a single (student) lead author. It’s great to BE the golden boy/girl, but much less fun to be one of the many in the shadows.
 This is not to say that incoming students won’t have ideas of their own, or have nothing to contribute. However, a PI is committed by way of grants and interest to particular topics and projects. Students to greater or lesser degrees control HOW projects evolve, but it will be some years before most can propose an entirely new research focus.
 A third type is occasionally seen, and is best typified by the phrase, “Somebody had to do it.” Their research output tends to mimic those who have lost their fire.
 Ie. Expect one or two one-on-one meetings per year.