Meta is Testing Custom Audience Expansion

When I logged into Ads Manager recently, I noticed a new alert at the top. I had been selected for an advertising study. Based on the description, it seems Meta is testing Custom AudienceThis is the group of people who can potentially see your ads. You help influence this by adjusting age, gender, location, detailed targeting (interests and behaviors), custom audiences, and more. More Expansion.

I know that’s not the best image. And I no longer see the message. But the full alert read as follows:

This ad account has been selected to participate in a 9-week study to help improve campaignThe campaign is the foundation of your Facebook ad. This is where you'll set an advertising objective, which defines what you want your ad to achieve. More performance. A small proportion of ads using Custom Audiences will be delivered to people beyond the Custom Audience. Expanding your audience is often an effective way to improve results, but you can opt out.

Next to the message was a button to opt-out.

First: Kinda cool to be part of a study!

Second: Oh, crap. What is this?

Let’s sort it out…

A Continuation of a Trend

Custom Audience Expansion would be a continuation of a trend. First, there was Detailed Targeting Expansion (which became Advantage Detailed TargetingWhen turned on, Meta can expand your audience to reach people beyond the Detailed Targeting (interests and behaviors) that you selected, but only if that expansion is expected to lead to better results. Location, age, gender, and exclusions are hard constraints, and the expanded audience will continue to follow those rules. More). Then there was Lookalike Expansion (which became Advantage Lookalikes). In each case, the approach was similar:

You pick an initial audience to target
If Facebook/Meta think you can get better results, the audience will be expanded

That is precisely what’s happening here with CUSTOM audiences now (at least that’s what this looks like). You choose a custom audience or group of custom audiences to target. But, if Meta thinks you can get more or better results by expanding outside of that custom audience, the audience will be expanded.

Lack of Transparency Regarding Reporting

One problem, which I keep making regarding expansion of detailed targeting and lookalikes, is that we just have to take Facebook’s word for it. Technically, the audience will only be expanded if and when you can get more or better results. In theory, it can only be used for your benefit.

But, there’s no way to confirm that it was helpful. There’s no break-down option to see things like:

How much your audience was expanded
How many conversionsA conversion is counted whenever a website visitor performs an action that fires a standard event, custom event, or custom conversion. Examples of conversions include purchases, leads, content views, add to cart, and registrations. More happened because your audience was expanded
The overall impact of expansion on your results

Because of this, we just have to trust the expansion, and that doesn’t feel right.

The Relevant Message Problem

One of the reasons remarketing is so powerful is that you can reachReach measures the number of Accounts Center Accounts (formerly users) that saw your ads at least once. You can have one account reached with multiple impressions. More people with extremely relevant messaging based on things like:

What they bought
What they viewed on your website
A specific action they performed

But, the way that you target these groups is with a custom audience. So, let’s say you create an ad targeting a custom audience with a very relevant ad — an ad that would be irrelevant to anyone else. We obviously would not want to reach someone outside of the custom audience.

I understand that there may be cases when expanding a custom audience may make sense. For example, if you’re targeting your website visitors generally to promote a product and you just don’t get the volume of traffic to exit the learning phase. Some expansion could be helpful.

But not always. In the example I describe, I absolutely do not want the audience expanded. Hopefully, it won’t be on at all times with an inability to turn it off. Of course, expansion always is on in some cases related to detailed targeting and lookalike audiences, so there’s reason to be concerned.