Why aren't more men working? (The New York Times, 6/15/2018)
The issue, in economist’s jargon, is labor force participation. When the Bureau of Labor Statistics surveys households, every adult is put into one of three categories. Those who have a job are employed. Those who are not working but are searching for a job are unemployed. Those who are neither working nor looking for work are counted as out of the labor force.
This last group is ignored when calculating the unemployment rate.