Don't know if you are interested in such things, but the following paper is highly enlightening. Most especially the Comments on it by Robert Topel of NBER & Univ. of Chicago.... following the body of the paper (starting on pdf "page" 58).  If you read nothing else in this link, read the Topel Comments which are a good summary of the essential elements of the paper PLUS plus add several well reasoned insights.

http://www.nber.org/chapters/c11245.pdf

Essentially the paper analytically desribes the long term effects of the baby boomer's entry and aging on the unemployment rate showing that about 80% of the unemployment changes over time from post-war to late 90's (when the paper was written) is due soley to shifts in the age demographics of the US population.... he also shows that (& provides both an analytic model and empirical proofs of same) there's little to no effect on aggregate unemployment rates as function of changes in educational attainment... other than perhaps over the very short term.   

An outgrowth of this paper is that comparison's of unemployment rates (&/or labor force participation rates) over time have no relevance to policies or other financial / business, gov't effects without first taking into account (and subtracting) the demographic effect.  Another is that changes in productivity and aggregate unemployment rates over time are not related... and Topel's comment explain why that is likely and expected to be the case 

File under things you ought to know a lot more about (in order to interpret policies and other published "data") but probably don't.