Must-Read: I really want to see what happens to these numbers in a high-pressure low-slack economy...
Where Have All the Workers Gone?: "Among male heads of household between the ages of 25-54...
:...[not at work,] 27 percent say it is because they are ill or disabled.... [But] we excluded from the sample anyone on disability.... Another 22 percent said they couldn't find work--not too surprising in a year when the unemployment rate was still over 7 percent. The remaining half... going to school, taking care of home or family... retired (despite being under 55), or... some other reason for why they weren't working.... These are all men in their prime working years and that their lack of work leaves them and anyone else in their household at or near the poverty line.... Women heading households are somewhat similar... with far fewer reporting that they are ill or disabled and more of them reporting that they are taking care of home or family...
http://www.brookings.edu/research/opinions/2015/11/17-where-are-the-workers-sawhill