Why is there such variation in PhD length internationally?

Question

I'm an undergrad in Australia, and at this stage I want to go on to do further study in maths (or maybe physics/CS, still have a few years till then).

Should I do so, I imagine that I will want to complete a PhD overseas. Possibly at a university in the US or maybe Oxbridge in the UK.

In Australia, PhDs typically take 3 or 4 years, and I would be eligible to go straight into a PhD upon completion of my undergraduate degree (it is research focused and includes an honours year, see here).

But, much of what I have found for overseas institutions has been in the range of 5-7 years, or maybe a 3-4 year PhD with a few years doing a master's degree beforehand.

Does this indicate that the level of rigour and amount of work produced is significantly different for various PhD programs, or is it the case that some programs are more relaxed and simply spread the same amount of work over a longer period of time?

Answer 1

In addition to @aeismail's points, in the U.S. the undergrad degree (B.S. or B.A.) in math is typically rather thin, due to "breadth" requirements, so a year or two of a PhD program is spent catching up, in comparison to most other educational systems in which specialization occurs earlier (and perhaps high school math education is more intense).

Some decades ago, it was the style in elite places in the U.S. to have people finish a PhD degree as quickly as possible, often in three years, as proof of ... something. This was plausible under the hypothesis that students at such places had an unusually good background.

In fact, given the way professional mathematics has evolved, spending more time learning things and maturing before hitting the job market may be wise. In any case, no one is creating artificial obstacles to any student's quick graduation! In my current institution, there really are no "required courses", in the sense that there are some modest proficiency exams in standard material that need to be passed, and courses help prepare for those, or can substitute for proficiency exams to some extent. Thus, a well-prepared student can "test out" of requirements.

One underlying problem seems to be that people take as much time as is allowed, so if it is understood that one may take six years "if necessary", then most people plan to use up that time. Not that they're "forced to" or "kept from graduating earlier". And then there's the reasonable fear of facing the job market that leads to "avoidance".

I would claim that "having to teach" is not a serious impediment to quick graduation. However, its relatively immediate gratification can seduce people away from the far-less-immediate gratification of research and study.

Answer 2

In the UK system (or similar systems, like Australia) students enter their Ph.D. program with a stronger background due to earlier specialization, and they typically leave their Ph.D. program at a less advanced level than a Ph.D. from a comparable American school. The difference is not in how fast people learn, but rather differences in what a bachelor's degree means and what a Ph.D. degree means.

Note that on specialization for undergraduates the US is the outlier, but in terms of Ph.D. outcome it's the UK that is unusual. For example, Chris Parks writes, "Across Europe the view prevails that the three-year UK doctorate is too short and thus of inadequate quality compared with the more common four-year doctorate."

Answer 3

The length of the PhD program depends on how the bachelor's and Master's programs are structured, and what additional demands are placed on students in terms of teaching and other assignments.

For instance, in the US, you can gain admission to a PhD directly after a bachelor's degree, but you will also be expected to take courses for one to two years. In mathematics especially, you will likely have significant teaching duties as well. in Europe, PhD programs in math will still likely require significant teaching, but no coursework, since it is presumed you took the requisite courses as a Master's student.

Answer 4

Another aspect that's worth mentioning is that there's PhD and there's PhD. Even though the name of the title is essentially the same when translated to common English, the "content" of the dissertation and diploma could differ significantly. If you have more time to do your research you're more likely to produce more publications (although this is not a given). I would even argue that the potential increase in your publications is not linear to the number of years in grad school, considering the rather steep learning curve.

Similarly the expectations during post-grad applications could also vary based on the degree. You might, and probably will, be expected to do more years of post-doc research before getting a faculty position, in comparison to if you had a longer PhD period (for instance 5 years instead of 3).

Yet another aspect is the funding; most PhD programs are limited in years, because the funding is usually limited in years. In other words, if you have means of sustaining yourself without grant money, or if your supervisor/group leader has the possibility to fix some other source of funding, I am pretty sure actual dissertation time would not be a huge issue (again it depends on the supervisor).

Lastly, none of this is written in stone, and there will always be exceptions to the rule. I would advocate that there is really no shortcuts to success, and instead of worrying about number of years to a particular title, one should focus on getting "really good/competent" at the field of research.

Answer 5

Having moved from the US to Europe (Denmark specifically), I was surprised that doctoral degrees here are standardized. Whereas in the US degree times vary considerably for all the reasons stated in the other answers, in Europe the length of PhD degrees is increasingly zeroing in on three years. Indeed, in Denmark no one is permitted to take longer than three years.

This is due to an international European standard known as the Bologna process, which aims to standardize academic qualifications across Europe. In order to enter a PhD in Bologna process countries, students must have a sufficient number of ECTS points (equal to a master-level degree), thus reducing the variance in times (common in the United States) due to differences in additional courses (minimal), teaching obligations (minimal), etc. between students, departments, and universities.

Answer 6

For those interested in why the U.S. is an outlier compared to Europe in terms of PhD length, it's important to keep in mind that European countries used to have not only widely varying standards for doctorates but also widely varying degrees (i.e., many countries had degrees that did not even map onto the BA-MA-PhD system). European countries are now increasingly standardized around a 3-4 year doctorate because all degree programs in (most) European countries are expected to follow the standards set by the Bologna Process, which fix the ECTS credit hours for particular degree programs. As a result 47 European countries (as of 2014) now have relatively standardized and transferable degree requirements, which differ quite dramatically from those in the U.S. higher education system.