What is the first step in the A/B testing process checklist?

• A. Set up tracking
• B. Define success metrics
• C. Plan the test and establish baseline
• D. Choose a variable to test

Answer: (D)

The first step is choosing the variable to test. In an A/B test, you need a concrete element to change and compare against a baseline, because the whole experiment is built around that specific difference. By selecting the variable—the element you’ll modify—you establish the hypothesis and define what you will measure. For example, you might decide to test whether a blue call-to-action button leads to more clicks than a green one. That choice sets the scope of the experiment, the data you’ll collect, and what success looks like.

Once the variable is defined, you can plan the test specifics, establish a baseline for that variable’s current performance, set up tracking to capture the right data, and determine what constitutes a successful outcome. Without picking a variable first, the test lacks a focused target, and subsequent steps become ambiguous or misaligned.