A/B Testing Framework

A/B testing (split testing) is the practice of randomizing users into two or more variants, measuring outcomes, and using statistical inference to determine which variant performs better. You change one thing (headline, button color, price, flow), run it on 50% of traffic, and measure conversion, revenue, engagement, or other metrics. The framework combines experiment design (hypothesis, sample size calculation, randomization), execution (traffic splitting, tracking), and analysis (statistical tests, lift calculation, confidence intervals). Discipline in all three stages is what separates rigorous teams from teams that confuse noise for signal.