Founder at Delivering Growth
Javid Jamae has led experimentation and growth engineering at Postman, Achieve, and Earnest, shipping roughly 150 product experiments across Postman, Skipcard, Tout, and Achieve and building the infrastructure under them: feature flagging, deterministic assignment, exposure logging, and analytics pipelines. He runs the Delivering Growth community and built the free A/B-testing calculators on this site. These days he also operates a portfolio of AI-run products, so the failures and numbers in these posts come from systems he runs himself.
Sample ratio mismatch (SRM) is when your A/B test split lands off target. Learn what causes it, how the chi-squared check finds it, and what to do next.