About 50,000 PhDs are minted each year in the US. Assuming a working life of 40 years, that means there are about 2 million PhDs in the domestic labor market.

About 50,000 PhDs are minted each year in the US. Assuming a working life of 40 years, that means there are about 2 million PhDs in the domestic labor market. Now take into account that: 1) For profit universities like University of Phoenix also issue PhDs. Most employers don't take them seriously, but USBLS measures them just the same. 2) We're in the midst of the worst job market in generations, and it may quickly become the worst job market since industrialization. Given these circumstances, having 5,000 people, or about 0.25% of the PhD-holding labor force, working as janitors does not sound like a particularly significant datum for making broader assumptions about the value of the PhD.