“Overproduction of Ph.D.s, caused by universities’ recruitment of graduate students and postdocs to staff labs, without regard to the career opportunities that await them, has glutted the market with scientists hoping for academic research careers. Long years of training and dismal career prospects form ‘a strong disincentive to American college graduates to enroll in doctoral programs,’ and early-career Ph.D.s have ‘little expectation of finding an academic research position that utilizes the training they received as a graduate student and a postdoctorate [sic] fellow,’ Research Universities states” (from “A Stellar Opportunity”, Science Career Magazine).
You would think that a large population of highly educated people would be a great thing for a country. The unemployment rate for astrophysics and math PhD’s is low because they can be used in many industrial settings, but for chemistry and biology Ph.D.’s the unemployment rate is higher.