If this is meant to be academic research (and I get the feeling it is), then it's unlikely they'd be able to use words as they're ordinarily used. Terms used will have to be clearly defined and stated in order to avoid confusion and misinterpretation (unless you're suggesting that such definitions already exist).

Unfortunately, this doesn't make it easy to discuss things outside the research field.

I'm not sure how else they could term it if they want a consistent label for all stages. Colloquially, it would be "they got too big for their britches", but that doesn't come across well in a study.

It would probably be better, though, to have phase-specific terms. It would probably make it easier to identify with each phase.

:) - I guess we can still improve on simplicity.