on behalf of the GEANT4 Hadronic Working Group. Abstract-The longitudinal and lateral dimensions of hadroninduced showers are fundamental aspects of the simulation of LHC calorimeters. In segmented calorimeters it is important that showers are precisely described by the simulation programs, since the experiments often rely on the segmentation to improve the energy measurement. In the paper we review the current status of the agreement between data and simulation. For integrated quantities, such

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... as response and resolution, there is generally very good agreement between data and GEANT4 ; shower shapes instead need additional attention and several studies are being performed in the GEANT4 collaboration to improve the agreement with data. The key aspects of the models having an impact on shower shapes will be reviewed and their agreement with experimental data assessed. Current limitations and possible solutions to improve the description of showers will also be discussed.