The main objective of the thesis is to demonstrate the importance of the union between promotional planning data and demand forecast in the optimization of the forecast itself. In particular, the aim is to demonstrate that even using algorithms of simple applications a significant increase in the accuracy of the forecast can be achieved. In addition, the secondary objective of this thesis is to highlight how the creation of a corporate culture based on the sharing of data and information between different departments, may lead to an improvement of the procedures and an optimization of the final result. An emphasis is to be put on how this type of approach can be a determining factor in obtaining a competitive advantage in the market..