🎯 Open Source

Marketing Measurement You Can Trust

Move beyond point estimates and gut feelings. Our Bayesian framework gives you honest uncertainty ranges so you can make decisions with confidence.

The Hidden Problem with Traditional MMM

When you run many models and only report the "good" ones, you're painting targets around arrows.

Specification Shopping

Traditional approaches often involve running dozens of model variations and selecting the one with results that "make sense." This feels rigorous but actually destroys statistical validity.

Watch the dartboard: each throw represents a model specification. Only the bullseyes (models with "good" results) get reported. The misses? Quietly discarded.

The result: Your reported 100% accuracy is an illusion. The real accuracy is much lower, but you'll never know because you only see the "winners."

Models Run 0
Models Reported 0

This Is Specification Shopping

The darts that miss are models with "unrealistic" results—quietly discarded.

Three Models for Different Needs

Choose the right level of complexity for your measurement challenge.

Standard MMM

Best for: Single outcome measurement

The foundation. Measures how media drives a single outcome (sales, leads, etc.) with proper uncertainty quantification.

Media Sales
Learn more →

Nested Model

Best for: Measuring indirect effects

Captures how media works through intermediate steps like awareness or consideration before driving sales.

Media Awareness Sales
Learn more →

Multivariate Model

Best for: Product portfolio analysis

Measures interactions between products—how promoting one SKU affects others (cannibalization or halo effects).

Promo Product A Product B
Learn more →
⚠️ Use with Caution

Principled Variable Selection

Traditional variable selection (stepwise regression, p-value hunting) is a form of specification shopping that invalidates inference. Our framework provides Bayesian alternatives that quantify uncertainty about which variables matter.

But variable selection is not a general-purpose tool. It should only be applied to precision control variables—never to confounders, mediators, or your media variables themselves.

Learn When & How to Use It

Posterior inclusion probabilities quantify variable importance

See Bayesian Updates in Action

Watch how prior beliefs combine with data to produce honest uncertainty ranges.

Adjust Parameters

Value: 0.3
Value: 0.5
Value: 50
Value: 0.5

Why Cross-Effects Matter

Promoting one product affects others. Ignoring this leads to inflated ROI estimates.

⚠️
Without cross-effects: Multipack promotion looks like pure incremental gain. Your ROI calculation overstates the true value.
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With cross-effects: Net portfolio impact is lower—some "lift" was shifted from single-pack, not created. Honest measurement leads to better decisions.
See the Math →

Explore the Documentation

Everything you need to go from your first model fit to a quarterly closed-loop measurement program.

Start here

Getting Started

Install the framework, fit your first Bayesian MMM, and walk through a complete code example.

For modelers

Modeling Guide

Step-by-step guidance for building statistically sound MMMs - priors, hierarchy, diagnostics, and iteration.

For media planners & CMOs

Interpreting Results

How to read MMM outputs, communicate uncertainty, and translate posteriors into confident budget decisions.

Measurement

Calibration Loop

Wire experiments and the MMM into one self-correcting cycle - EIG, EVOI, and the virtuous loop.

Foundations

Bayesian Workflow

The disciplined Bayesian process: priors, prior predictive checks, fitting, posterior diagnostics, and PPCs.

Foundations

Causal Inference

DAGs, do-calculus, and counterfactuals - the causal scaffolding behind every defensible MMM specification.

Methodology

Variable Selection

When to include precision controls, why confounders are non-negotiable, and how shopping for variables backfires.

For sponsors

For Business Stakeholders

The risks of specification shopping and what defensible measurement looks like for agencies and brands.

See it run

Demos & Reports

Interactive workflow demonstrations, scenario analyses, and an example MMM report from a Q4 2025 fit.

Reference

Technical Guide

Math and implementation details for every model in the framework - standard, nested, multivariate, and combined.

Reference · Sphinx

API Reference

Module-by-module API docs (Sphinx). Browse the source on GitHub or build locally with make html in docs/api.

Reference

Glossary

Definitions of every term used across the docs - adstock, EIG, EVOI, MFF, ITT, MDE, ROPE, and more.

Reference

FAQ

Common questions about MMMs, Bayesian methods, and the trade-offs the framework makes deliberately.

Project

Versioning & Changelog

Current version, API stability tier per module, versioning policy, and release notes.

Project

About

Background on the framework, its design principles, and the audiences it serves.

Ready for Honest Measurement?

The framework is open source and ready to use. Start with our documentation or dive straight into the code.