Originally Posted by indigo
If "too many" are going to grad school, does this mean that there may be more grad students that what the institution can place as research assistants and teaching assistants? Or what is "too many"... how does one determine the threshold?

"Too many" does indeed mean that there are more students than can be placed in jobs in the field. The problem is worst in the humanities, but affects the sciences as well.

Humanities: article in Slate

STEM: The Atlantic

And on and on. Just google something along the lines of "phd can't get job."