A/B Testing Non-Deterministic AI Features: Why Your Experimentation Framework Assumes the Wrong Null Hypothesis
Your A/B testing framework was built for a world where the same input produces the same output. Change a button color, measure click-through rate, compute a p-value. The variance comes from user behavior, not from the feature itself. But when you ship an AI feature — a chatbot, a summarizer, a code assistant — the treatment arm has its own built-in randomness. Run the same prompt twice, get two different answers. Your experimentation infrastructure was never designed for this, and the consequences are worse than you think.
Most teams discover the problem the hard way: experiments that never reach significance, or worse, experiments that reach significance on noise. The standard A/B testing playbook doesn't just underperform with non-deterministic features — it actively misleads.
