Using Bayesian Priors in MMM: Do Better‑Looking Results Mean You Have a Better Model?

February 20, 2026By Simon FosterAdvertising Evaluation, Market Mix Models, Marketing Effectiveness, Marketing Mix Models, MMM

There is an active and polarising debate about whether Bayesian priors should be used in MMM. Broadly speaking there is a progressive group of academics and practitioners who argue that the use of Bayesian prior values, effectively applying guideline results bounds to your model, makes models more flexible and insightful. And on the other side … Read More

Techniques to evaluate marketing uplift experiments

August 7, 2025By Simon FosterAdvertising Evaluation, Marketing Effectiveness, Media Evaluation

Experiments are an important way to validate marketing effectiveness measurement.  This post will take you through some approaches to evaluating marketing uplift experiments. Let’s assume you run a test TV / VOD campaign over 4 weeks in March 2025. How can you measure the sales revenue uplift it created? In this post, we’ll look at … Read More

What is incrementality in marketing – extracting trend, seasonality and brand equity

December 11, 2024By Simon FosterAdvertising Evaluation, Marketing Effectiveness, Marketing Training, Media Evaluation, MMM

Marketing incrementality is sales revenue that is over and above that which might be expected with no marketing activity. Establishing incrementality is critical if you want genuine brand growth. Why? Because many performance platforms collect, report and even double-count sales from multiple sources, including those which might happen even if you didn’t run any activity. … Read More

Maximising Media Effectiveness and Efficiency

March 1, 2022By Simon FosterAdvertising Evaluation, Market Mix Models, Marketing Effectiveness, Marketing Mix Models, MMM

This is a piece I wrote for an m/SIX newsletter in January 2022. Effectiveness and efficiency are not the same but they are both critical in media strategy, planning and activation Intro Marketing effectiveness and campaign efficiency are intertwined terms across the open plan workspaces of both advertisers and agencies. But they mean very different … Read More

What is Marketing Mix Modelling (MMM)?

November 20, 2021By Simon FosterMarket Mix Models, Marketing Effectiveness, Marketing Mix Models, Media Evaluation, Media Planning, MMM

Marketing Mix Modelling or MMM is a regression-based approach to identifying the drivers of sales for a business or brand – making it a form of attribution.  For many advertisers it is used to understand and optimise the effects of paid media in generating short and medium term sales outcomes.  Unlike many other forms of … Read More

Adstock and Diminishing Returns: non-linear advertising effects

June 7, 2020By Simon FosterMarketing Effectiveness, Marketing Training, Media Planning, MMM

Adstock is an important concept in marketing effectiveness. It was first quantified by Simon Broadbent in the 1970s. Its value lies in helping make marketing and media mix models more accurate by recognising that advertising and media investments have non-linear “carryover” response effects. These non-linear effects are normally grouped into two areas: the delayed effect … Read More

What is full funnel attribution in marketing?

March 21, 2020By Simon FosterMarketing Training

Imagine this situation. You work in a large organisation as a digital marketing manager. You observe a sharp increase in GA direct, organic and brand generic web traffic. You want to explain the uptick but there’s nothing in your digital data that can explain it. However, you do know that your brand launched a TV/AV … Read More