[whatever1]

Not really. In most of the departments in the US you are expected to start research in parallel to your classes at the end of the first semester. The latest I know of, is the end of the second semester after the course-based qualifier exam that many departments still have.

Within 12 months you are expected to do full time research regardless of what other obligations / selective classes you have.

So more like 4+ years of full research. Many schools have avg PhD program durations way over 6 years.

In UK post doc is almost a must for those who really want to dive deep.

[chrisseaton]

How can you do 'full time research' as well as being an instructor for taught classes? Does not compute.

Day one of my UK PhD I was shown to my desk, told to start researching, and that was it. I didn't waste any time with any classes or teaching (I did actually teach for a couple of hours as a favour.)

As long as you can produce top-tier papers during your PhD then you're meeting the international standard.

[whatever1]

>How can you do 'full time research' as well as being an instructor for taught classes? Does not compute.

Yep this is where the gruesome part of the American PhD comes. And that is why in the first two years of the program the attrition is huge. In my class 50% had dropped by the end of year 2.