It does. College and high school. The Bureau of Labor Statistics defines the labor force as anyone over age 16 who is not on active duty in the armed forces and who is not in an institution (prison or mental facility, old age home, etc.) That figure includes retired, those not working due to choice like stay-at-home mothers, those on disability, and so forth. So yes, that 21.5% rate is skewed. That's why the government does not use it as a measure of unemployment.
Well, we need another major measure of labor force participation then.
It is NOT a measure of how good or dire the labor market is to include those who are in school and those who are retired.
That's exactly right. There are employers all over this country who can't even fill their open positions today. Knowing that, I'd suggest that the vast majority of the unemployed people in this country fall into one of two categories:
1. They aren't interested in working because they don't need to work for a living (i.e., retirees).
2. They are unemployed because they are unemployable for one reason or another.