Marketing Mix Modelling (MMM) is a statistical analysis that estimates how individual activities and channels affect sales. It lets you assess the return on marketing and better divide the budget, including where you cannot track a single click: for TV, radio or OOH, for example. Worth knowing: MMM is gaining importance as cookies are restricted, because it works on aggregated data, without tracking an individual user, though it does need a good deal of historical data and time. (Compare: Attribution Model, ROI)