system
Given the following post, respond as if you're commenting on Reddit:
human
Why do some people jump straight into a PhD program without doing an MS first?

Looking around at a few CVs, I noticed how common this was. Why is this? I thought the usual case was to get a BS then an MS then a PhD.
gpt
That's the usual pattern in most of Europe, but not in the US.  In the US, most masters programs in the sciences are "terminal masters" programs: they're designed for people who aren't planning to pursue a further degree.  (That's not to say some people don't, just that it's not the focus of the program.)

Instead, US PhD programs are often a bit longer, because students spend the first one to two years primarily taking courses.  That is, the first one to two years of an American PhD program are basically equivalent to a masters program.