Why is it important to verify that your test is the only A/B test running for a campaign or webpage?

• A. To ensure that results are not affected by other ongoing tests, leading to clearer insights.
• B. To speed up data collection.
• C. To reduce the number of variants.
• D. To comply with regulatory requirements.

Answer: (A)

When you run an A/B test, you want the data to reflect only the change you’re testing. If another test is active on the same campaign or webpage, visitors can be exposed to multiple variations, creating interactions between experiments. This contamination makes it hard to attribute any observed lift to the specific change you’re evaluating and can bias results, distort effect sizes, and delay reaching statistical significance. Keeping tests isolated ensures traffic is cleanly randomized to the experiment, so the measured impact is truly due to the change under test. It also helps maintain a stable baseline and reduces confounding factors, yielding clearer, more reliable insights into what actually drives performance.