The European Central Bank published a working paper finding that aggregate EU labour force participation changes little after regional growth shocks, even as employment falls and unemployment rises for four to five years. Based on EU Labour Force Survey microdata covering 15 countries and 114 regions from 2000 to 2020, the study suggests the unemployment rate captures aggregate cyclical slack more reliably in the EU than in the U.S., although an increase in inactive people who want to work points to hidden slack. Aggregate stability masks substantial differences across groups. Men’s participation declines after negative shocks while women’s remains stable, reflecting sectoral segregation and the added worker effect. Participation among workers aged 15 to 24 can remain depressed for up to eight years, while less-educated and non-native workers face disproportionate employment losses. The findings indicate that aggregate slack measures may overlook distributional effects relevant to monetary policy and support targeted labour market interventions for vulnerable groups.