We are about halfway through the campaign build flow. We've created a new campaign in one of the available placements, added our content, which can be a personalized content experience, a product recs carousel, or product badges, and defined our audience.

You might not always want all of the people in your audiences seeing the campaign you've built. This might be because you are not confident in the result, and you need to manage that risk, or because you are looking to A/B a campaign. So in this step, we'll look at how you'll decide what percentage of an audience sees the campaign.

INFO: The people that don't see the campaign will see your default website content, often referred to as the control. FYI, if we are going to use the correct term, the campaign would be the variation.

Let's look at the choices.

• 50% - this is a good choice for campaigns when you are trying out something completely new for your website. This might be a new style of messaging, new promotions that you've never run before, etc. 50% of the people in the audience will see the campaign, and 50% the control
• 95% - this is a good choice for campaigns when you need to reach out to as many people as possible, especially when you are trying to deliver on actions that came out of your weekly trade meeting, but still need to monitor your campaign's performance against goals. 95% of the people will see the campaign and 5% the control
• 100% - this is a good choice for campaigns when you want to reach out to all of the people in an audience and are confident that your campaign will have a positive impact on goals. With this option, there's no A/B testing and therefore no performance comparisons

INFO: You cannot select 100% when you have chosen to replace your control because it would mean none of your visitors would see your baseline variant.

Go ahead and select one of the available audience splits Click Save and continue to move to the final step in the build flow

When you make a selection, we'll estimate the number of people that will see the campaign each week. This estimate is based on the last seven days of data from your property and the attributes you've defined for your audiences. In our example, we see the estimation is 27,000:

INFO: It's worth considering that the more narrow the focus of an audience, the lower the number of people that will see your campaign will be. You can confirm this by reviewing the estimation for each of the audience splits.