• By measuring the relative effectiveness of different versions of a marketing campaign.
• By both requiring a holdback group to determine which version of an ad performs better.
• By typically requiring a smaller sample size and less sophisticated statistical analysis.
• By determining the impact of ads on a consumer’s decision to convert or not convert.

The Correct Answer is : By determining the impact of ads on a consumer’s decision to convert or not convert.

Explanation: Incrementality experiments differ from A/B experiments primarily in their methodology and goal. Specifically, incrementality experiments determine the impact of ads on a consumer’s decision to convert or not. They compare the behavior of control and treatment groups, using a holdback control group that doesn’t see the ad, which sets them apart from A/B experiments where no such holdback group exists and two versions of an ad are simply compared for performance.