Wrong. The labor force increases due to population growth,
it doesn't have to. Let's say 10,000 kids turn 16, nobody dies or otherwise leaves the country. None of the kids is working or looking for a job. Population has gone up, labor force has not.
but with a lower participation rate, 1.7M less people are in the labor force than would have been if the participation rate had not decreased.
Ummm it's the people leaving or not joining the labor force that caused the participation rate to decrease.
I'm not really sure you're clear on the definitions here...
Population: All people 16 years and older not in prison, the military, or a mental institute
Labor Force: Employed (working) plus unemployed (not working but looking for work).
People not working or looking for work are Not in the Labor Force.
So the Labor Force Participation rate is the percentage of the (adult civilian non-institutional) population that is in the Labor Force.
Let's say there's a town with an adult population of 150 people, where 95 have jobs, 5 are trying to get jobs and the rest are retired, students, stay at home spouses etc. Pop is 150, Labor Force is 100, so LF participation rate is 66.7% (UE rate is 5%). 5 kids turn 16, none need a job, all are students, so none are working or looking for work. Population is now 155, Unemployment is still 5, Employment is still 95, UE rate is still 5%, but LF participation has now dropped to 64.5% NOBODY HAS LEFT THE LABOR FORCE in this scenario.
So, applying the same math the "if the LF participation rate hadn't changed", to this scenario, 88.7% of 155 is 103.. the difference is 3, add those to the unemployment level is 8, and 8/103 is 7.8% and we would reach the conclusion that the UE rate should "really be 7.8% because that's what it would be if the LF participation rate hadn't changed."
Horseshit.