If I'm not mistaken, most PhD students (at least in the sciences, which is the field I'm most interested in) are funded. They're provided with a stipend, and all tuition fees are waived. In other words, it's effectively a low-paying job for them. My question is, why fund PhD students instead of postdocs?

I'm dismissing the altruistic reason ("we fund PhD students as a service to the community") immediately since it doesn't make sense - presumably if someone is spending money in this fashion, they'd fund need-based scholarships. The only other reason I can think of is that the department wants something out of the PhD students - presumably research output; can't think of anything else - that they think they're getting a good deal on.

Now according to Google, the typical PhD stipend is about $20-25k / year. Meanwhile, the typical postdoc is paid $47k / year. That means that a department can hire approximately one postdoc per two PhD students. To that we can add:

  1. Postdocs have already been trained; PhD students are in training. Postdocs should hit the ground running while PhD students take time to get up to par.
  2. PhD students especially in 5-year programs spend the first couple of years taking courses, i.e. not doing research work.
  3. Postdocs can do other things like supervise Masters students that PhD students can't.
  4. PhD students apparently have a high attrition rate, as high as 50%. Postdocs have been in the business longer, so presumably are also more aware of what they're going into.

It seems more sensible to me that departments should concentrate all funding on postdocs, and leave PhD students to pay for their own education. This is already the case for undergraduate studies. Why do departments continue to fund PhD students?

  • 17
    Which country? Because things vary enormously from country to country. Jan 4, 2018 at 22:21
  • 3
    As aside, you're missing the PhD student's tuition and fees on both sides of the equation. Depts can both pay them but also get them depending upon the school. In some school, a PhD or post-doc will cost the same depending upon tuition. Jan 4, 2018 at 22:25
  • 8
    At least in Germany, this is totally different. PhD students are paid like normal employees, resulting in about 46k€/year or even more. Postdocs earn more. Many PhD students also supervise Master's Theses, this is not limited to Postdocs. PhD students do not have many courses in the first years and can mostly focus on research. However, there may still be several projects coming from the industry. Most PhD students are publicly funded. Well-educated PhD students will return this investment in later years.
    – J-Kun
    Jan 4, 2018 at 22:34
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    If you don't fund PhD students, you eventually run out of post-doc candidates. Plus, you seem to have a peculiar view of how PhD students are funded, which depends on country and institution...
    – Jon Custer
    Jan 4, 2018 at 22:36
  • 5
    What a bizarre worldview. You seem to reason exclusively based on economical matters. Fortunately the world doesn't revolve around money. The so-called "altruistic" reason doesn't make sense only if you don't look past your wallet... This is also obviously short-sighted as others pointed out: there's maybe an oversupply of postdocs now, but what about in 10 years when everybody stopped funding PhD students?
    – user9646
    Jan 5, 2018 at 11:30

7 Answers 7


"I'm dismissing the altruistic reason"

Therein lies one of the biggest problems with your question. I work for a land-grant state university in the U.S. Our mission includes education. It's not an altruistic reason, it's literally why we exist.

The other flaw in your question is assuming that the money to hire these two groups is fungible - it isn't always. For example, there are grant programs where education of graduate students is a major component of what one is supposed to be doing - "we're going to hire a postdoc" is simply a non-alloweable use of funding.

There are some other nice features of graduate students to consider as well:

  • They're cheaper. While a postdoc is probably more value for complex activities, there are sometimes things that require some expertise, but not a full-blown PhDs worth. Masters and early-stage PhD students are excellent people to conduct literature reviews, field collection, etc.
  • You can identify promising researchers early. Lets say you see someone in undergraduate courses whose impressed you. If you only recruited postdocs, you're essentially saying "Look me up in 6 to 8 years, I'd love to work with you." If you recruit graduate students, you can usher them into their research career.
  • You get them for longer. Postdocs are (by and large) transient positions, and much of their time may be taken up by looking (rightly) for another position. In many labs, especially those without long-term technicians, graduate students may actually have more institutional knowledge.
  • Thanks for the answer. Follow up question - if part of the reason for funding PhD students is because it's the university's mission, why not fund more scholarships? Both need-based or merit-based, as opposed to blanket-funding all PhD students? On that point as well I'm now wondering why undergraduates pay for their own education but PhD students don't, but that might be more appropriate for a separate question.
    – Allure
    Jan 7, 2018 at 11:17
  • @user3727079 That's really the content of it's own question.
    – Fomite
    Jan 8, 2018 at 2:10
  • Can someone provide specific examples of "grant programs where education of graduate students is a major component of what one is supposed to be doing"?
    – Eike P.
    Aug 18, 2021 at 16:11

One of the premises of your question is simply incorrect in the US. Since most of the funding for postdocs and PhD students in the sciences comes from grants and the usage of that money is specified by the grant and approved by the funding agency, departments can't simply decide to spend the money differently.

Furthermore, in the US, postdocs can be considerably more expensive than PhD students.

For a Postdoc you've got to pay full time salary, plus fringe benefits (typically 30% on top of salary) plus overhead on the salary and fringe benefits. For example, a postdoc might cost $50K in salary per year, $15K per year in fringe benefits, plus another $35K per year (54%) in overhead for a total of $100K per year.

For graduate students the costs include a stipend, fringe benefits (typically much lower for graduate students than postdocs, e.g. 2% at my institution), tuition waiver (varies a lot between universities), and overhead (on stipend and fringe benefits only, since tuition waivers are excluded from overhead.) A student might cost $25K per year in stipend, $1K per year in fringe benefits, $20K per year in tuition, plus $15K in overhead (58%), for a total of $61K per year.

In these calculations, a postdoc was almost twice as expensive as a graduate student. Also notice that the postdoc costs three times as much in overhead as the graduate student. Many program managers hate to see funds going to overhead. For these and other reasons, there's a widespread preference in the funding agencies for funding graduate students rather than postdocs.

  • Thanks for answer. Follow-up question: if funding agencies hate to see funds going to overhead, why do they preferentially fund researchers who are affiliated with universities? When I asked about why researchers needed universities a few weeks ago I got the sense that to apply for most grants a researcher needed to be affiliated to a university, even though the university takes some overheads if the researcher wins the grant.
    – Allure
    Jan 5, 2018 at 2:48
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    @user3727079 there is a lot of research that only ever gets done in an university environment, because its exploratory research, something that may or may not turn into profit for an hypothetical investor (a lot of grants are given by research councils or whatever is similar in your country). Not to say that any company will charge you way more than the salary of the person doing the job if you want them to do anything. Still, most university research, even in engineering, is not funded with the idea of obtaining profits in the near future. Jan 5, 2018 at 9:13
  • "Furthermore, in the US, postdocs can be considerably more expensive than PhD students." It can also be the other way round. Take Harvard for example, a postdoc is cheaper than a PhD because the PI does only need to pay for salary and not salary + tuition.
    – user64845
    Jan 5, 2018 at 13:32
  • The major alternatives to universities are the DOE national labs and the research labs associated with the military services. Overhead rates at these labs are typically higher than at universities. SBIR grants are an interesting example of grants to companies, but only small businesses can participate. Jan 5, 2018 at 15:33
  • @DSVA Probably tuition cost of a grad student should be the net cost, so whatever the university collects from the department as "tuition" minus whatever the department gets back as their cut of revenue for enrolling the student. I'd be amazed if this is $20K. Jan 6, 2018 at 0:42

Adressing your points:

  1. I find this only partially true. The spread inside each population in competence is larger than the distance between the populations.

  2. (+4.) PhD students - if motivated and good - will stay until you give them the PhD. Others (not motivated, not good) will leave early. Postdocs are less easy to control and may be more prone to doing politics. Typically the motivated postdocs will change when it fits them best (e.g. after having a good publication) and the others may stay

  3. That is purely theoretical. Wherever I looked, PhD students had other functions in the lab, too.


  • people can be assessed and trained during their PhD - if they are good they may stay.

There are several reasons, here are some:

  • The most important one, IMHO, is that the reputation of the department depends a lot on how many good PhD students they can produce. This will affect the ability to obtain funding, attract (masters/undergraduate) students, etc.
  • There are some grants that are only enough to fund PhD students, or that can only be used to fund PhD students.
  • Advisor to PhD student can be considered academic parent, advisor to postdoc is just another employer.

It seems more sensible to me that departments should concentrate all funding on postdocs, and leave PhD students to pay for their own education.

In Computer Science (and STEM in general), if you don't fund PhD students, not many people will do it. If one can have a PhD offer from Stanford, s(h)e can also get a job offer from big five (Amazon, Google,...) with a six-figure salary. And you want them to work for free in 5 - 6 years?


A few additional points that I have not yet seen mentioned.

First, many funding agencies have an explicit preference or even requirements that the funding be used to fund PhD students rather than postdocs. If your main funding sources don’t want to give money for postdocs, it’s hard to have them.

Second, tenure-track faculty members are usually expected to shepherd some number of PhD students to their degrees as part of the expectations for receiving tenure. You can’t do that if you only hire postdocs.

That said, postdocs are useful, and having an excellent postdoc does “pay for itself” several times over in terms of cost.


Another point that hasn't yet been mentioned is that it's not always correct that research output is what PhD students are being paid for. Especially at large American universities, PhD students are paid for teaching, often for leading discussion sections rather than lecturing courses as the main instructor. A postdoc is generally too senior to serve as a teaching assistant in this way, so there is a constant stream of money from undergraduate tuition to graduate student stipends.

  • Aren't PhD students usually just TAs, while postdocs can be entrusted with teaching a full course?
    – Allure
    Sep 11, 2020 at 6:12
  • @Allure Precisely—but at a school with a large lecture model, there is a need for many more TA’s than professors. This model is surely cheaper than smaller lectures led mainly by postdocs, and allows undergraduates at least some exposure to full professors, even at huge schools. Sep 11, 2020 at 6:35

In general, postdocs are expected to be able to write good scientific texts and have some reputation in their field. In particular, they are expected to be able to attract their own funding by writing research/grant proposals. This is not how it should be: postdocs are good at research and should concentrate on it, "converting coffee into theorems" (or, more generall, money into research)! But this is how it is, and is unlikely to change.

  • This seems to be a comment rather than an answer, primarily expressing agreement with the premise of the question.
    – Nat
    Jan 6, 2018 at 21:12
  • @Nat The question was "Why", and my first two sentences say why.
    – user85520
    Jan 6, 2018 at 21:28
  • I'm not sure that I follow. It seems like the observation that postdocs are expected to obtain their own funding is something like a restatement of the situation rather than an explanation for why it's that way. With regards to causation, it looks like you basically just said that it shouldn't be this way, "[b]ut this is how it is, and is unlikely to change". Not to be aggressive, just not seeing how this addresses the question about why things are this way.
    – Nat
    Jan 6, 2018 at 21:33
  • @Nat Within the scope of my post, that postdocs are able to obtain their own funding is a premise, and that the faculties prefer them to take care about their own funding themselves is a conclusion. If you want to understand why postodcs are able to obtain their own funding, ask a different question.
    – user85520
    Jan 6, 2018 at 21:48
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    To restate the question, "My question is, why fund PhD students instead of postdocs?", they're asking about why departments put their funds into PhD students over postdocs. Your point that postdocs are able/expected to get funds on their own seems like a valid observation, though I'm unclear how we get from that valid observation to a causal reason that departments wouldn't choose to put their funds into postdocs instead of PhD students. This is, why aren't departments using their funds to get even more postdocs instead of PhD students?
    – Nat
    Jan 6, 2018 at 21:58

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