This weeks Economist has an article subtitled, "Why doing a PhD is often a waste of time" (subscription required). Many of the items reported are familiar for those who read phds.org, but a few new things stood out:

PhD production is growing rapidly outside the US. This means possibly additional opportunities in overseas universities, but greater competition for filling them.:

Between 1998 and 2006 the number of doctorates handed out in all OECD countries grew by 40%, compared with 22% for America. PhD production sped up most dramatically in Mexico, Portugal, Italy and Slovakia. Even Japan, where the number of young people is shrinking, churned out about 46% more PhDs.

This statistic was particularly striking:

the production of PhDs has far outstripped demand for university lecturers. In a recent book, Andrew Hacker and Claudia Dreifus, an academic and a journalist, report that America produced more than 100,000 doctoral degrees between 2005 and 2009. In the same period there were just 16,000 new professorships.

I'm puzzled by their PhD production numbers - 100,000 sounds pretty low to me - but the 6-to-1 ratio of PhDs to professorships sounds similar to what I've heard for the fraction of life sciences postdocs that ever get tenure track positions. Indeed, from Richard Freeman:

There is a glut of postdocs too. Dr Freeman concluded from pre-2000 data that if American faculty jobs in the life sciences were increasing at 5% a year, just 20% of students would land one.

PhDs outside of academia often end up doing things not closely related to their studies, so their advanced degrees don't buy them much additional earning power:

A study in the Journal of Higher Education Policy and Management by Bernard Casey shows that British men with a bachelor’s degree earn 14% more than those who could have gone to university but chose not to. The earnings premium for a PhD is 26%. But the premium for a master’s degree, which can be accomplished in as little as one year, is almost as high, at 23%. In some subjects the premium for a PhD vanishes entirely. PhDs in maths and computing, social sciences and languages earn no more than those with master’s degrees. The premium for a PhD is actually smaller than for a master’s degree in engineering and technology, architecture and education.

The suggested remedies are standard fare: better training in transferable skills and better metrics.

One interesting concrete realization of the training improvements is the UK's New Route PhD (trademarked!).