Which is the average age in which persons start their PhD? Is this age in some way related to the post PhD plans a person does?
In my (European) experience I have 3 groups of people, with the relative distributions:
- (70% of the total) Those who started right after graduation (let's say when they were 24) without any job experience. Most of them (with exceptions, of course) are a bit fed up with research and willing to try a "real world job experience"
- (25% of the total) Those who started 2,3,4 years later (so between 24 and 29), taking a full time phd. Generally people belonging to this group seem to be more motivated for academic career, even if starting a phd when one is 29 years old might be a bit late (or not?)
- (5%) Those who start in their 40ties with the idea of taking a part time PhD as an out of job activity, and don't plan to leave their job.
Clearly there are all the possible shades between the above categories.