If you want to test a manual bidding strategy against an omnichannel Smart Bidding campaign, which technique should you use?

Campaign Experiments allow you to test changes to your campaigns, such as bidding strategies, against your existing setup. This is ideal for comparing a manual bidding strategy with an omnichannel Smart Bidding campaign, as it lets you allocate a percentage of your budget and traffic to the experiment, ensuring a controlled comparison. Incrementality measures the true impact of advertising by comparing a group exposed to ads with a control group that isn't, but it's not designed for A/B testing bidding strategies within a campaign. User-based and Geo-X are methodologies for measuring incrementality, often involving holding out specific users or geographic areas from seeing ads, rather than A/B testing campaign settings.