The approach showed in Fig. 1 was designed to account the real-world data challenges in all the steps of the analysis with the involvement of clinical experts. This is the first study of ED flows using healthcare production data with this wide a large overview regarding data information, processes, and interaction with hospital wards and external processes. From the multi-objective analysis (Fig. 1, steps b-c) it emerged that there were multiple sources that led to the ED overcrowding. These rely on both