When designing an A/B test for a Mail.ru mobile ad, what factor requires the *mostcareful consideration to avoid skewed results?

When designing an A/B test for a Mail.ru mobile ad, *ensuring equal and random distribution of users across the different ad variations is the factor requiring the most careful consideration to avoid skewed results. A/B testing involves comparing two or more versions of an ad to determine which performs better. If the users are not randomly assigned to each variation, or if one variation is consistently shown to a specific demographic group, the results may be biased and not accurately reflect the true performance differences between the ads. For example, if ad variation A is primarily shown to users with high-end devices and ad variation B is shown to users with low-end devices, the results may be skewed by device performance rather than the ad creative itself. Proper randomization ensures that each variation has an equal opportunity to be seen by a representative sample of your target audience, leading to more reliable and accurate test results.