ACKNOWLEDGEMENTSThis work was done in the context of a research partnership between theInstitutdes politiques publiquesand theDirection de l’Animation de la Recherche, des Etudeset des Statistiques(Dares) at the French Ministry of Labor. We thank the Dares forits financial support that made it possible to realise this study.Our partners at the Dares have also provided several suggestions that dramat-ically improved the quality of the report. We would like to thank in particular fortheir useful feedback Cécile Ballini, Mathilde Gaini and Philippe Zamora. We alsothank them warmly for their patience and flexibility throughout the project.We then thank warmly the IPP team for constant support with the project. Weare particularly grateful to Julien Grenet as he suggested the central idea that isinvestigated in Chapter 4 of this report, and provided insightful comments through-out the project. Marion Monnet also deserves to be thanked for participating in themanagement of the project at its initial stage, and helping throughout.This report was written after the organization by the Dares and the IPP of aworking group on skills and skill mismatch. We would like to thank all participantsand their institutions for their feedback when we presented preliminary versionsof our work to the group. We also thank the OECD which allowed us to access aslightly enriched version of the PIAAC data, which was very useful to undertake theanalyses presented in the report.