About Meridian GeoX

Geo experimentation (or incrementality testing) is a modern measurement methodology that isolates the true causal impact of marketing campaigns by running controlled tests across distinct geographic regions. Geo experiments compare regions where a marketing variable is changed against regions where it remains the same, anchoring your marketing strategy in causal reality and measuring incremental lift independent of publisher attribution.

Meridian GeoX is an open-source solution for measuring cross-publisher incrementality. By providing cookieless and publisher-agnostic measurement, it helps close data gaps and generates ground-truth experiment data used to calibrate Marketing Mix Models (MMMs). The library offers cost-effective, multi-cell testing with flexible methodologies. It integrates seamlessly with Meridian (MMM) to provide the causal measurement needed to inform MMM priors.

Meridian GeoX helps you answer key questions such as:

• What is the true incremental impact of my media spend across a specific platform or channel globally?
• Which experiment design (such as holdback, go dark, or heavy up) is best suited to test my specific business objectives?
• How can I use proven causal results to calibrate my Marketing Mix Models (MMM) and improve budget allocation?

Core benefits

The revamped methodology in Meridian GeoX offers reliable incrementality testing that is both cost-effective and time-saving. Benefits of using Meridian GeoX include:

• Streamlined all-in-one solution: Functions as a single library for all current and future methodologies, covering both study design and incrementality analysis. It also allows for comparing study designs across different methodologies.

• Tailored experiments: Provides support for many types of experiment designs to support your needs, including holdback, go-dark, and heavy-up.

• Multi-cell capability: Enables multi-cell execution, which saves both cost and time by comparing multiple treatment arms with a common control group.

• Flexible design: Offers a flexible API to accommodate operational constraints or geo and statistical constraints in study design, such as forcing certain geos to be excluded from testing to avoid large media disruptions.

• Meridian MMM integration: Seamlessly integrates with Meridian Marketing Mix Model (MMM), by suggesting new GeoX experiments for your Meridian model based on MMM results. These experiments help calibrate your model by using GeoX's open-source library to test and compare real-world data across different methodologies to provide incrementality-driven priors.

Installation

Prerequisites and system recommendations

Python requirements

• Meridian GeoX only: Python >= 3.10 is required for Meridian GeoX
• Meridian GeoX and Meridian MMM: Python >= 3.11 is required to use alongside Meridian MMM.

GPU recommendations

Meridian GeoX relies on JAX for high-performance vectorized computations. Installing meridian-geox will automatically install CPU-based JAX. If you plan to run heavy simulations or use JAX acceleration for both GeoX and Meridian, we recommend setting up JAX with GPU support. Refer to the JAX installation guide and the Meridian installation guide for GPU configurations.

Install the Meridian GeoX library

To install meridian-geox, run the following command to automatically install the most recent published version from PyPI:

$ pip install --upgrade meridian-geox

To install or upgrade both google-meridian and meridian-geox from PyPI, run:

$ pip install --upgrade 'google-meridian[meridian-geox]'

Alternatively, to install the development version directly from GitHub:

$ pip install --upgrade git+https://github.com/google/meridian-geox.git

How to Use the Meridian GeoX Library

• Demo Colab: Check the Getting Started Colabs for a complete interactive walkthrough of single-cell and multi-cell designs and analysis.
• Methodology: Read the research paper for a deep dive into the library's core components, statistical methodology (Time-based Regression, etc).

Meridian GeoX Documentation & Tutorials

For full technical documentation, mathematical formulations, and step-by-step guides, visit the official Meridian GeoX Documentation:

Support

Questions about methodology: See Design methodology in the technical documentation.

Issues installing or using Meridian GeoX: Feel free to post questions in the Discussions or Issues tabs of the GeoX GitHub repository. The GeoX team responds to these questions weekly in batches, so please be patient and don't reach out directly to your Google Account teams.

Bug reports: Please post bug reports to the Issues tab of the GeoX GitHub repository. We also encourage the community to share tips and advice with each other on the Issues tab. When our team addresses or resolves a new bug, we will notify you through the comments on the issue.

Feature requests: Please post these to the Discussions tab of the GeoX GitHub repository. We have an internal roadmap for GeoX development, but welcome your inputs for new feature requests so that we can prioritize them based on the roadmap.

Pull requests: These are appreciated but are very difficult for us to merge because the code in this repository is linked to Google internal systems and has to pass internal review. If you submit a pull request and we believe that we can incorporate a change in the base code, we will reach out to you directly about this.

Citing Meridian GeoX

To cite this repository:

@software{meridian_geox_github,
  author = {Google Meridian GeoX Team},
  title = {Meridian GeoX: High-Performance Framework for Geographic Incrementality Experiments},
  url = {https://github.com/google/meridian-geox},
  version = {0.1.0},
  year = {2026},
}