Displacement index of colleges since 2022

Since 2018, the DEPP has calculated an expulsion index for each college each year. This continuous index is the synthesis of a set of complementary variables related to remoteness. It is obtained by means of a principal component analysis (PCA). The variables used to calculate the index capture different dimensions of the geographical distance of colleges and correspond, for the most part, to the distance between the college and a point of interest (students’ place of residence, certain training courses, equipment, …). Until 2021, these distances were calculated as the crow flies. They are now calculated in travel time by means of a new reference road distancer made available to the DEPP by INSEE. This distancer relies on an OSRM (Open Source Routing Machine) routing server, which makes it possible to calculate optimal road journeys on the fly, from point to point, with great speed of execution, throughout France and at the border. This new calculation method makes it possible to measure distance more closely to the topography of journeys between establishments and points of interest, particularly in mountain areas. To facilitate understanding, from the start of the 2022 school year, it was decided to set the median of the index at 100, which means that the value of the index is less than 100 for half of the least distant colleges and more than 100 for the most distant half. The interpretation of the index remains unchanged: the higher the value and the greater the distance.