The new Balanced Scorecard (BSC) model is an effective tool for the evaluation and monitoring of the financial and non financial companies performance. To improve its efficiency, we have added two new perspectives: health and safety at work and the environment. In order to define the cause-and-effect relationship between the six perspectives of the new BSC model, we have selected a case study of a Moroccan medical analysis laboratory. Indeed, this laboratory is working to consolidate its leadership in its field or sector of activity at regional and national scales through its commitment to the ISO 9001 quality management system and a steady improvement of its performance and efficiency. In this context, it implemented a system of performance indicators. Accordingly, we classified these indicators according to the six axes of the new BSC model. Then, we studied the cause and effect relationship between the six perspectives using the DEMATEL method (Decision-Making Trial and Evaluation Laboratory).