The Experimenteurs Toolkit - Pre/Post test statistics, estimated impact

About

**🆕 New for v3!**

• Hypothesis builder — document your experiment hypothesis directly on saved projects
• "Go to projects" quick link after saving an analysis
• Pages & Audiences — save page configs with instant run time and MDE reference tables for any target uplift
• CSV export for all saved projects
• Pre-test usability nudge — highlights missing fields when you try to calculate run time
• Bonferroni correction toggle on pre-test calculations (4+ variants)
• Refreshed UI with inline clear controls, trash icons, and polished project cards

---

**The Experimenteurs Toolkit** is a lightweight side panel calculator for anyone running A/B tests. No sign-ups, no data sent anywhere — everything runs locally in your browser.

**Pre-Test Planning**
Calculate the three numbers you need before launching any experiment:
• Minimum Detectable Effect (MDE) — know the smallest uplift your test can reliably detect
• Sample size per variant — based on your baseline conversion rate, target uplift, and significance level
• Estimated run time — enter your daily visitors and see how long the test needs to run

Supports custom significance levels (90%, 95%, 99%, or any value) and automatically adjusts for multiple variants. Bonferroni correction available when running 4+ variants.

**Post-Test Analysis**
Enter your control and variant data to get:
• Frequentist results — conversion uplift, 95% confidence intervals, p-values, and significance
• Bayesian results — chance to beat control via Monte Carlo simulation, credible intervals
• Revenue projections — estimated incremental revenue per month with confidence intervals
• Visual comparison charts — conversion rate bars with CI overlays, chance-to-win bars

Add as many variants as you need. Each gets full statistical treatment.

**Estimated Impact**
Quantify what a successful experiment could be worth:
• Monthly and annual revenue projections based on your traffic, conversion rate, and expected uplift
• Helps prioritise which experiments to run first

**Saved Projects**
Track your experiments from planning through to results:
• Save pre-test analyses as named projects
• Add post-test data later — results are auto-inferred from your frequentist table
• Record outcomes (won/lost/inconclusive), actual uplift, significance, and incremental revenue
• Add a structured hypothesis to sharpen your thinking before you run
• Export everything to CSV

**Pages & Audiences**
Save your key pages and audiences with their traffic and conversion data:
• Instant reference tables showing run time, sample size, and MDE for 5%, 10%, 15% uplift targets
• Custom uplift row — type any percentage and see results live
• MDE pills showing what you can detect in 7, 14, and 28 days
• Optional AOV for revenue projections

**Privacy**
All data is stored locally on your machine using Chrome's built-in storage. Nothing is sent to any server. No accounts, no tracking, no analytics.