The operating rooms (OR) in hospitals is a complex system, with a high number of innovations every year. Therefore the healthcare professionals (HCPs) are required to choose between the several aspects and innovations for the OR. Decision-making requires a mutual vision (Littlejohn et al., 2017) and should be based on evidence (Turner et al., 2017). To improve the well-informed decision-making, the main research question is: “How can a decision-support tool for optimisation in the operating room help a healthcare professional to select the objectives and the assessment criteria for performance optimisation of the operating room and the optimisation impact?”. The evidence for the tool consists of the 223 relations between the objectives and the assessment criteria (metrics) and 253 causalities of metrics that express the impact. There is a high heterogeneous perspective on the objectives of the optimisation of the performance of the OR and the criteria of assessing the quantification of (the optimisation of) the OR performance, which makes it harder to create a mutual vision on the OR performance. To achieve a mutual vision, a holistic view and consider all the perspectives, including the impact of optimisations, the HCPs should all share their perspectives on the objectives and the situation should be considered in its whole (Leinonen et al., 2008; Littlejohn et al., 2017). Therefore, the decision-making process could benefit of a decision-support tool. In this study a new tool is developed, namely the Performance Operating Room Counselling (PORC-)tool. This tool provides a holistic view of the OR performance (optimisation), by displaying evidence of the relations between objectives and metrics and the causalities. It also supports a conversation, which could lead to a mutual vision (Littlejohn et al., 2017). The tool is based on the concepts flowchart, matrix table and Microsoft Excel, for respectively the roadmap, the information display and the running-programme. The PORC-tool consists of an Excel file, a brochure and a manual with a more elaborated version of the functionality and the steps. The PORC-tool provides a clear and structural overview with evidence, to gather information more easily, provides multiple perspectives on the OR performance and supports to gather more insight into the OR organisation and goals before the decision-making of the HCP. The PORC-tool should be validated in practice and the functionality should be approved by HCPs. In the future, the tool can also be extended on perspectives, field of interest, aesthetics and functionality. To conclude, the answer to the main research question is that the HCPs should be facilitated to consider the whole complex system in their decision-making process, and support the decision-making based on evidence and with a mutual vision.