The official unemployment rate is defined as "total employed, as a percent of the civilian labor force," but doesn't include a number of employment situations in which workers may find themselves. The U-6 rate is defined as all unemployed, "plus all persons marginally attached to the labor force, plus total employed part time for economic reasons, as a percent of the civilian labor force."
In other words: the unemployed, the underemployed and the discouraged.*
Some people prefer the U-6 measurement which still has a little ways to go to meet the pre-Financial Armageddon values (about 1% lower). U-3, however, is at pre-Financial Armageddon values.
I haven't seen this sort of figure before (see below). I find it very interesting. all in all, it looks like the employment picture is pretty good with wage increases above 2% (in fact 3% according to one report.**). So far so good. Note that the ratio now is significantly higher than before the Financial Armageddon of 2008-2009, but below the roaring 1990's.
It seems as if there is a problem finding workers qualified to fill OPEN employment slots.
* http://www.cnbc.com/2017/04/07/us-reported-4-5-unemployment-rate-but-realistic-number-is-higher.html
** http://lowcountryceo.com/news/2017/04/us-wages-increase-3-march-year-over-year-according-glassdoor-local-pay-reports/
http://www.reuters.com/article/us-usa-economy-idUSKBN16H0KA
