We plan to carry out a study on atypical employment (understood as any form of mobilization of labor other than standard employment under permanent contracts such as the fixed-term contract or temporary work) in hospitals in France. One purpose is to measure the extent of any additional cost related to the use of atypical employment more precisely, beyond what was achieved in the context of the Véran report (2013) - for which it is impossible to know which data were collected - to therefore highlight the impact on the distribution of health resources. We also seek to understand the impact that the mobilization of a workforce with fragmented careers can have on the organization of care, the quality of services rendered, and working conditions. The quantitative study that we wish to carry out with the requested confidential data will be supplemented by a qualitative study within French hospital services.