Many academic programs in the humanities don't even admit Masters degree students. They admit only PhD students, and a Masters degree is simply a certificate yo

Many academic programs in the humanities don't even admit Masters degree students. They admit only PhD students, and a Masters degree is simply a certificate you get for satisfying the pre-dissertation requirements on the way to the PhD. There's no independent value to the Masters, and anyone in those programs who leaves school with a Masters is essentially a "failure", because they didn't complete their doctorate, the true goal. So it would be no surprise that these have a negative ROI. In these cases, you can't even get a non-tenure-track teaching position with a Masters degree, because there are already plenty of PhD graduates to fill the positions. (It would be interesting to see the ROI of PhDs, by the way.)