They’re VERY different!
If you are trying to decide between pursuing a PhD in the US vs a PhD in the UK, you should think more about which fits you best. There are 11 major differences between the two systems and you need to choose the one that fits you best:
#1 Masters Degree
Typically, in Europe, you would join a PhD program after completing your Master’s degree. In the US, you would spend a few years taking courses (alongside research) to get your Master’s degree.
If you already have a Master’s degree, you may get a course waiver, which could reduce the time needed to complete your PhD.
Most of the US universities ask for GRE and TOEFL in your application for PhD program. But this not mandatory for European, including UK and German universities. Though TOEFL, preferably above 90, is highly recommended for international students.
#2 Choose your project before starting your PhD
In the UK (and Europe), you typically choose a project before starting your PhD. This is different from the US, where you typically apply to a department for your PhD first and your thesis and research evolves in a year or two.
#3 No classes
There are no class requirements for a PhD in the UK. You begin your research right away. The assumption is PhD students know their research areas. After all, you start by applying to a professor / lecturer with a research area in mind.
Now, that might be true for some students. Others may want to get exposed to new ideas and potential research topics. In addition, they may also want to have a wider peer group that gets formed in classes.
#4 Time to completion
PhD programs in the UK (and rest of Europe) take around 3 to 4 years to complete. In the US, a PhD may take up to 5 or 6 years.
After a PhD in the UK, students generally go on to their postdoctoral research. After a PhD in the US, students tend to go directly from graduation to academia or research jobs without a postdoc.
In many UK (and European) universities, there are firm guidelines on just how long a PhD takes and those are more important than individual decisions by a student’s advisers. In comparison, in the US, some students can fly through their PhD in 3 years with tremendous amounts of research, while others can take as long as 8 to 10 years to complete their PhD.
There are different systems within Europe.
In Sweden and other Scandinavian countries, a PhD takes 4 to 5 years and includes additional teaching duties. Students in these schools are considered as employees. They receive monthly salaries which are comparable to the salaries earned by graduate students working in various industries and are taxable as well. A PhD student is allowed to either present or attend at least one conference anywhere in the world, expenses for which are taken care of by the research group.
In Germany, a 4-year PhD is considered too long and funding might not be available after the first three years of the PhD program.
#5 Work-life balance
This point is less about the PhD in question, and more about the cultural difference between the UK (and Europe) and the US, but this could be a factor in your decision making if you are particular about the type of culture around you and the kind of lifestyle you wish to have.
The PhD lifestyle is much more relaxed in the UK (and in Europe). You will have more time for yourself as well as your friends and family in the UK, while pursuing your PhD.
In the US, PhD students are often overworked with more teaching and grading responsibilities. They also have a lot of class work.
#6 Hierarchical structure
In the US, PhD students report to and directly interact with their professors, but some of the PhD programs in the UK are headed by the Professor but there is also a Reader and a Lecturer. Students sometimes feel this hampers their flexibility to work, while restricting their exposure to the lab as well as the head of the lab.
#7 Future opportunities
Some students feel that the US offers more opportunities to PhD students in academia as well as jobs. This can be true as the US has many universities offering teaching positions as well as companies offering jobs to PhD students. However, irrespective of whether you earn your PhD from Europe or the US, some experts say you may have to hustle to find a great job after your PhD.
#8 Different stipend (salary)
For most PhD in the UK (and Europe), stipend (or salary) comes centrally from the universities or from Government research organizations. These stipends (or salaries) may be limited to only 3 years.
In the US, stipend (or salary) comes directly from your supervisor without any limitation on the duration of the PhD. Unlike in big US universities, there are fewer TA responsibilities for PhD students in UK universities.
In many cases, you don’t need to pay tax on your income as a graduate student in the UK (and Europe).
In Germany, international PhD students are funded for 3 years by the German government.
#9 Less publications
In the UK, you have less chances of getting published. Your time is more focused on your thesis document.
#10 Less chance of faculty position afterwards
In the US, students opt for faculty positions after receiving their PhD. This isn’t necessarily the case with PhD students in the UK, who opt for postdoc positions to remain in academia.
#11 More similarity than differences
The UK (and European) universities are being influenced by the US system. Many UK universities’ Computer Science schools have Doctoral Training Programs which are essentially 4-year PhD programs, with the first year focused on teaching. These programs offer more flexibility about what you end up doing and who you end up working with. Also, these programs often are sponsored by industries, which means these have higher stipends and you may get an adviser in industry.
So, which one to choose – UK (or Europe) PhD vs US PhD?
Apart from the factors mentioned above, you should focus on the quality of the research group and reputation of the professor. You should look at the top conferences about your topic of interest and note where the papers come from. That’s your best clue as to which university / school you should choose.