First, mix models measure advertising and promotion effects only among total sales rather than among penetration versus repeat purchases.

FORBES: The Downside Of Marketing Mix Models Is There's No Upside For CMOs

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.

FORBES: The Downside Of Marketing Mix Models Is There's No Upside For CMOs

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.

FORBES: The Downside Of Marketing Mix Models Is There's No Upside For CMOs

The current conventional understanding of how advertising and promotion work and how spending should be allocated has been greatly determined by marketing mix models.

FORBES: The Downside Of Marketing Mix Models Is There's No Upside For CMOs