Estimate lift, conversion impact, and confidence for your Geo Holdout experiments. A must-use tool for data-driven marketing and media budget decisions.
Why It’s Useful for Online Marketers and Business Owners:
- Empowers smarter scaling with clear, data-backed business metrics like CPIA and iROAS.
- Helps validate if your advertising spend leads to real incremental conversions.
- Offers actionable insights before, during, and after a geo-holdout campaign.
- Dynamically explains test design, allocation, and analysis results in plain English.
- Reduces guesswork and improves confidence in marketing budget decisions.
- Eliminates dependency on black-box platform attribution.
Module 1: Geo Experiment Design – Power Calculator
Why Geo Experiment Design is Required:
Before launching any holdout experiment, it’s critical to ensure the design has enough statistical power to detect meaningful results. Running underpowered experiments can waste time, budget, and effort without producing actionable insights.
What Geo Experiment Design does:
This module calculates the statistical power based on your expected weekly conversion volume, budget, holdout percentage, target cost per incremental acquisition (CPIA), and test duration. It determines whether the experiment can reliably detect a lift if one exists and explains the outcome in easy-to-understand terms.
Why Experiment Design Is Necessary for a Geo Holdout Test:
A poorly designed test can produce false negatives, leading marketers to conclude that a campaign failed even when it did not. Power calculation ensures your test is built on a solid statistical foundation, helping you avoid wrong conclusions.
How to use it:
Input your expected weekly conversions, estimated weekly budget, target CPIA, holdout percentage, and planned test duration. The tool will calculate whether your experiment has enough power to detect meaningful lift and guide you if adjustments are needed.
Geo Experiment Design – Power Calculator
Module 2: Geo Holdout Test – Group Allocation
Why it is required:
Geo-holdout tests rely on fair comparison between “Test” and “Holdout” regions. Random assignment alone is not enough; balanced stratification based on past performance ensures more trustworthy results.
What it does:
This module takes your past 30-day city-level data (conversions and spend) and assigns cities to “Test” and “Holdout” groups. It uses stratified random sampling by distributing the data into high, medium, and low conversion groups and fairly splits each segment based on your holdout percentage.
Why it is necessary for a Geo Holdout Test:
A biased allocation could invalidate your test, making it impossible to tell whether ads drove real growth. Stratified sampling ensures both groups start from an even and comparable baseline.
How to use it:
Upload your CSV file with city-level data including City Name, Spend, and Conversions. Enter your desired holdout percentage. The tool will automatically create an optimized split and allow you to download the group allocation CSV for use in your campaign.
Geo Experiment Design – Group Allocation
Upload your CSV with City Name, Spend, Conversions columns (last 30 days data). This tool will assign each city to a Test or Holdout group using a stratified random sampling approach.
Module 3: Geo Holdout Test – Result Analysis
Why it is required:
After the test period ends, you must determine if the observed difference between your test and holdout groups was statistically significant and quantify the true value created by your campaign.
What it does:
This module calculates the lift in conversions, incrementality factor, cost per incremental acquisition (CPIA), incremental revenue, and incremental ROAS (iROAS). It also provides the confidence level of your observed lift and explains what it means for business decision-making.
Why it is necessary for a Geo Holdout Test:
This is the final and most important step that turns raw data into decision-worthy insight. It tells you whether the extra conversions observed in the treatment group were likely driven by your marketing efforts or just random chance.
How to use it:
Enter your total conversions and total spend for both Holdout and Treatment groups, and optionally your AOV (average order value). The tool will calculate all relevant metrics and explain the confidence level behind your results so you can make informed budget and strategy decisions.
Geo Experiment Design – Result Analysis
Enter the total conversions, spend and optionally AOV for your Holdout and Treatment groups. This tool calculates Incrementality, CPIA, Revenue, iROAS and explains your results.
The Geo Holdout Test Tool helps you move beyond guesswork and platform attribution by offering a statistically sound way to measure the real impact of your marketing campaigns.
From planning your test setup and allocating cities to interpreting final results, I crafted this tool to ensure that each step is clear, validated, and business-focused. Whether you are a marketer optimizing ad spend or a business owner looking to measure true ROI, this tool empowers you to make smarter, data-driven decisions with confidence.
Stop relying on assumptions. Start validating your marketing impact with the Geo Holdout Test today!
