Test2x2 has an interesting development journey that spans over a decade:
📱 aStat - The Beginning
Originally developed as "aStat" when smartphones were just emerging. The HTC Desire was all the rage, and Android API was still at level 4. This tool was designed for convenient calculation of 2×2 contingency table statistics, NNT/NNH, and confidence intervals for proportions.
⏰ Years of Dormancy
aStat gradually became outdated due to lack of maintenance. Many technical specifications (such as privacy policies) were left incomplete, eventually leading to removal from Google Play Store in 2022.
🤖 AI-Assisted Rewrite & Rebranding
Using LLM tools (including Claude AI), the project was revived as a React prototype on a0.dev platform, then transformed into a native Android app with Kotlin. We discovered that "aStat" was already being used by multiple companies and statistical software products. To avoid potential legal issues, we decided to rebrand and focus specifically on 2×2 contingency table analysis, releasing it as Test2x2.
Postscript: During the rewrite process, I discovered that confidence interval estimation methods like Wilson's score (which required reading research papers and finding code back in the day) are now standard practice in R. We hope you enjoy this modern revival of a classic little tool! 🎉