There's an article in the Chronicle of Higher Education that's been getting a lot of recent attention. It's titled "Grad School in the Humanities: Just Don't Go". The author, clearly (and to my mind, justifiably) embittered about what he sees happening, is an associate professor of English who sees no need to produce a huge surplus of people who want to go on to become associate professors of English.
Some of his warnings don't apply to the sciences. The biggest difference is that there have always been many more places to find work with a science degree other than academia, which is not so true if you've concentrated your graduate studies on the life of Rainer Maria Rilke. Another key factor is that we don't generally come out of grad school with academic debts. To be sure, a Rilke scholar would learn an awful lot about sponging money off wealthy people, but there's that pesky poetic talent problem to be dealt with before you can put those techniques into practice. . .
Of course, these days the jobs aren't exactly coming so readily for new science graduates, although we're still in better shape than anyone over in the humanities. A lot of people are rethinking grad school, though, if the mail I get is any indication. For what it's worth, I offer the Chronicle author's list of bad reasons why people take on graduate study in the humanities - let's take a look and see how many apply to the sciences. I'm going to number them for easy reference:
(1) They are excited by some subject and believe they have a deep, sustainable interest in it. (But ask follow-up questions and you find that it is only deep in relation to their undergraduate peers — not in relation to the kind of serious dedication you need in graduate programs.)
(2) They received high grades and a lot of praise from their professors, and they are not finding similar encouragement outside of an academic environment. They want to return to a context in which they feel validated.
(3) They are emerging from 16 years of institutional living: a clear, step-by-step process of advancement toward a goal, with measured outcomes, constant reinforcement and support, and clearly defined hierarchies. The world outside school seems so unstructured, ambiguous, difficult to navigate, and frightening.
(4) With the prospect of an unappealing, entry-level job on the horizon, life in college becomes increasingly idealized. They think graduate school will continue that romantic experience and enable them to stay in college forever as teacher-scholars.
(5) They can't find a position anywhere that uses the skills on which they most prided themselves in college. They are forced to learn about new things that don't interest them nearly as much. No one is impressed by their knowledge of Jane Austen. There are no mentors to guide and protect them, and they turn to former teachers for help.
(6) They think that graduate school is a good place to hide from the recession. They'll spend a few years studying literature, preferably on a fellowship, and then, if academe doesn't seem appealing or open to them, they will simply look for a job when the market has improved. And, you know, all those baby boomers have to retire someday, and when that happens, there will be jobs available in academe.
Reason #1 is probably common, to some degree, across all academic fields. Graduate school is, in fact, largely about finding out whether you have enough dedication to get through graduate school (and is used as a credentialing signal for that very reason). Reason #2 also probably happens to some extent everywhere, but in science research programs there often aren't any grades after the first year. You have to get your validation from getting good ideas and getting your research to work, with is the same situation that obtains in the real world of science.
Reasons #3 and #4 are actually some of the things that keep people in grad school too long. Though the environment can be odd and stressful, you come to feel at home in it, and worry about going to some new situation where you won't have a place that you've made for yourself. Everyone in the sciences has known people in grad school who've stalled out for just these reasons.
Reason #5 doesn't apply as much for the sciences, I'd say. The kinds of jobs available to someone with just an undergraduate degree are often much different than the ones open to people with graduate training. And the material that you learn in grad school is much like what you started to learn as an undergraduate, just more of it and in more detail. The biggest change is in actually applying it to real research, instead of just learning it and doing well on a written test about it. That's another transition that throws some people out of a scientific career.
But reason #6 would definitely seem to apply, both for academic and industrial jobs. I'd have to think that we have a lot of people who are taking a bit longer to finish their PhDs than they might have otherwise, and a lot of people looking for post-docs who might otherwise not have done one, while they wait for the job market to improve. . .