If you are going to look at participation rates, I find its best to look at the age, gender and race breakdowns to understand which changes are cyclical and which ones are driven more by demographics and cultural changes.

https://www.bls.gov/emp/tables/civilian-labor-force-particip...

For example, there have been huge upticks in 55+ labor participation rates and huge downtrend of teenager participation over the last 20 years.