What capability does a cookie-based split provide for the testing process?

• A. It directs returning users back to the same campaign, improving result accuracy
• B. It redirects all users to the control
• C. It randomizes all users every time
• D. It eliminates the need for a control group

Answer: (A)

Cookie-based splits keep returning users in the same variant by storing their assignment in a browser cookie. When a user first lands, they’re randomized to a variant and that choice is saved. On later visits, the system reads the cookie and sends the user to the same campaign variant again. This continuity reduces variation from a user seeing multiple variants across sessions, making it easier to attribute any observed differences to the variant itself rather than changing exposure. It preserves the integrity of the comparison while still using initial randomization, though it’s worth noting that clearing cookies or using a different device can reset the assignment.