[zura]

First two years in the US PhD is like a master's degree studies - regular lectures/courses. That is way US PhD program is usually 5 years long and you apply with Bachelor's degree.

In Europe, mostly, you're required to have a master's degree to apply for a PhD.

[Fomite]

That's not particularly generalizable to U.S. programs - a good 3/4ths of the PhD programs I applied for expected a Master's before hand.

I'm also not sure how its relevant to what I said?

[zura]

I see. I meant that hardest part can be that initial 2 years of US-esque 5-year PhD. Overall, in US, PhD is student - teacher relationship, while in Europe, mostly, it is employee - employer relationship.