I think this is, at some level, a relative question; the “expected placement” for various programs differs wildly and the bandwidth of that expectation also varies, often between specialties. In American politics, at least, supply and demand are pretty well balanced; my “travails” on the market probably have had more to do with my personality as an interviewee and my pickiness when it comes to job opportunities than a placement issue. On the other hand, if I defined success not as “a tenure-track job” but “a tenure-track job in a doctoral program”—which is how many of the faculty and graduate students I’ve interacted with over the years at ICPSR and EITM have defined it—my career is destined to be a failure, since I have no real interest in such a job except as a means to obtaining another job (I suppose now is as good a time as any to offer my apologies to those PhD-granting departments I applied to under semi-false pretenses).
Those who are skeptical that any single, useful, standardized measure of placement can be adopted are probably right, although there are some surveys available that get at the basics, and I think this answer gets to the crux of the situation for the potential student:
Programs with a good placement record will keep track of placements and brag about them.
If you can't get a straight answer from a department/program, THE REAL ANSWER SUCKS.