Which fracturing model to use?   Why are model results different from field observations? Based on the outcomes from the 2nd ARMA (American Rock Mechanics Association) Hydraulic Fracturing Workshop, this talk highlights the various physics involved in hydraulic fracturing, as well as the model showcases to capture them. Providers of twenty fracturing models participated in seven benchmark case studies with standardized input and output requirements. The models used in the study ranged from legacy 2D, pseudo 3D, planar 3D, to fully coupled 3D, state-of-the art models. In general, all participants successfully demonstrated their model’s validity in capturing various physical phenomena. As expected, differences in the models for each case studied were observed. These differences arose because of different inherent assumptions/simplifications, theoretical backgrounds, numerical approaches, physics incorporated, etc. One should keep in mind and appreciate these differences when selecting a fit-for-purpose fracturing model.