Unfortunately, these models are fundamentally flawed in being biased to favor corrosive price promotion over brand-building advertising and to favor advertising cost efficiency over sales-growth effectiveness.
As a result, mix models understate the value of advertising and overstate the value of price promotion, producing a systematic bias that favors price promotion over advertising.
The current conventional understanding of how advertising and promotion work and how spending should be allocated has been greatly determined by marketing mix models.
In this age, incompetence is no barrier to promotion, and failed states like California and Illinois are taken not as examples to avoid but as models to emulate.