The Question on People Leaving the Labor Force is 41-Year-Olds, Not 61-Year-Olds

In his discussion of today's employment report Neil Irwin notes that the unemployment rate is considerably lower than would otherwise be the case because so many people have simply given up looking for work and are therefore not counted as being unemployed. Irwin then adds that the big question is that if the economy eventually recovers is:

"How many of the 61-year-olds who gave up looking for a job in the last few years are going to return to the labor force when they smell opportunity, and...