Meridian (Google MMM)

What Is Meridian?

For marketing decision-makers, Meridian solves a long-standing problem: it shows data-based evidence of which channel contributes how much to business success. Unlike last-click attribution, it also accounts for the influence of channels that don’t appear directly before a purchase. This enables more informed budget decisions between SEO, ads, and social media.

Meridian is Google’s open-source Marketing Mix Model (MMM) that helps businesses measure the impact of various marketing channels on their business outcomes and optimize budgets across all channels. Unlike click-based attribution, Meridian analyzes the relationship between marketing spend and business results at an aggregate level and across all channels, including offline media.

Technically, Meridian is based on Bayesian statistics and uses a hierarchical model that accounts for regional and temporal variations. What makes it unique: Google provides proprietary data with Meridian that would otherwise be unavailable — such as reach and frequency data from YouTube and Google Display. This data significantly improves model quality, since classic MMMs often use only spend as input.

In practice, Meridian is especially relevant for businesses with significant budgets across multiple channels. It answers questions like: which channel delivers the highest incremental return? Where do I reach the point of diminishing marginal returns? The model supplements incrementality testing and causal impact analyses with a strategic planning layer. Since Meridian is open source, you can adapt it to your specific requirements.