One major difference between UK and US undegraduate courses is that when you study undergraduate at a UK university, you _only_ do courses in your chosen course of study. No faffing about for a year or two picking a major, no time spent filling language requirements or taking interesting-sounding courses to scratch an itch. As a result, UK graduating undergraduates tend to have spent more time in their chosen field of study than US undergraduates have. It has plusses and minuses: I (UK grad) would have loved to have followed my diverse interests more; but on the flipside I do know more about my subject than my US equivalents. I have no proof but it's reasonable to think that would transfer to shorter PHD programs.
Germany's basically the same. I've lived here 20 years. I went to a liberal arts college in the US. Shortening the time to getting a PhD is the only argument I could make for the European system vs. a liberal arts system. German even has a word for people who are knowledgeable in their field and nothing else: "fachidiot" (literally field-idiot). Even aside from being a well-rounded individual, the number of times it's helped in my career that I had to take university-level general education classes is huge.
Even with my liberal arts background, and having worked in pretty mathy areas of industry, it's rare that I, say, have to use much from my last two years of CS education. (What they did prepare me for is getting to the point that I can read research papers in areas I've since worked in.)
To be clear: virtually everywhere in the US a CS curriculum takes 4 years. There's no deciding in year three and graduating on time. You could potentially switch to CS from engineering, math or physics and get close.
In Germany at least, in contrast to the US, there's no coursework in a PhD, which I believe is the main thing that makes a PhD shorter than, say, a US PhD directly after a bachelors degree (which is typical in the sciences).
If I recall correctly, the exception is in Scotland, where the undergraduate programs tend to be more like America's: 4 years of study with emphasis on broad liberal arts education in secondary and higher education. I remember when applying for colleges in the U.S., our councilors noted that while it's virtually impossible for an American to apply as a full-time undergrad at English schools, particularly Oxbridge, due to incompatibilities in our educational systems, it's perfectly feasible to go from an American high school to a Scottish undergrad program (aside from the obvious travel and visa hurdles).
Not exactly sure about the UK specifically, but elsewhere in Europe you can absolutely take any course that the university offers - it just wont be accredited and you will gain 0 ECTS Points, which you need to collect in a timely manner to complete your degree.
Yes you generally can in the UK too, just ask the lecturer as a courtesy at least, if there's capacity they'll probably be pleased someone's keen, but might ask you don't submit any problem sheets or whatever for grading.
That's not what GP means though: in the first year in the US, generally speaking, undergraduates aren't enrolled on a particular programme; they take a range of courses from different faculties for credit, and decide which area to 'major in' (and perhaps additionally 'a minor') later.
It's the same in France as in the UK. I'd say 90% of my time in college was spent on things directly related to maths, computer science or software engineering. Sports was mandatory for the first 2 years and half too.
> I have no proof but it's reasonable to think that would transfer to shorter PHD programs.
I didn't enter one (regretfully) anywhere - but from what I recall when looking, US/Can typically have more of a taught element in preparation, included in the first year or two of the PhD programme.
Sort of like doing an MPhil or something followed by PhD I suppose, but built-in and I assume designed to counter the effect you describe.
