In A/B testing, what is the purpose of success metrics in the test plan?

• A. They provide a framework to judge whether the test achieved its goals
• B. They are optional
• C. They only track budget usage
• D. They replace the need for a hypothesis

Answer: (A)

Success metrics define what counts as a win in an experiment. They provide a framework to judge whether the test achieved its goals by tying observed results to the business objectives you set in the plan. By predefining metrics and the thresholds that indicate a meaningful improvement, you can make objective decisions when the data arrives, determine the needed sample size and duration, and decide whether to roll out the winning variant or run further iterations. These metrics align with the hypothesis and focus the analysis on outcomes that matter, rather than budget details or chance fluctuations. They are essential and not a replacement for a hypothesis.