Have a high CPA? Don’t know why your ads are not working? Ad fatigue could be hurting your performance and you may not be aware. It is is the silent killer in many Facebook ad accounts.

If you don’t know how to spot and stop ad fatigue from happening in an account. You can waste a lot of time and money going after the same person.

The Facebook Story

3+ billion people. That’s how many people use Instagram, Facebook and the WhatsApp platform. Facebook was the first site to reach a billion people and now they are well past 2.2 billion. Their strength and weakness is one and the same, however. That being the number of people you can target with your advertising.

If your audience is to small, you’ll saturate your audience quickly with your advertising. People will get bored and turned off from your brand, so you don’t want to annoy people right out of the gate. Go after an audience that’s too large (say a million plus) and you might spread your budget too thin. Something to consider: if you have multiple audiences over a million in size, you might have people who reside on more then one of your audience lists at the same time.

If this happens, then the handy Facebook Overlap Tool is something you need to understand. This is an often overlooked and yet a vital tool in your Facebook marketing tool kit, and can be fond in the audience section of Facebook.


Steps to Using The Facebook Overlap Tool

  1. Go to Audience in Facebook
  2. Select the audiences you want to compare in Facebook (up to 5)
  3. Click Three Little Dots next to the Delete button and then “show audience overlap”
  4. Figure out if your audiences overlap

A couple important Notes from Facebook:

  • The first audience you select will be listed first as the “Selected Audience.” Every other audience you select will be listed in the “Comparison Audiences” section. You can change the selected audience by choosing a new one from the dropdown in the upper-right corner of the tool. You can choose from any of the audiences you selected.
  • You can only get useful overlap information from audiences with at least 10,000 people, so consider that when selecting which audiences to compare.

The overlap tool will show your “Overlap” and the “% Overlap of Selected Audience” for each of your comparison audiences. The “Overlap” number is showing you how many people are in both audiences. The “% Overlap of Selected Audience” will show you how many people are in both audiences vs the total number of people in the selected audience. This is how Facebook gets to show the percentage of overlap between the two audiences.

A good examples might be an ecommerce store looking to target people who show an interest in Nordstrom (Audience A) and Topshop (Audience B). If you pick an audience with 100,000 people (Audience A) and a comparison audience of 1,000,000 people (Audience B), and there are 50,000 people that are in both audiences. The number 50,000 remains constant no matter which audience is “selected” and which is “comparison.” However, the percentage of overlap will change if you switch which is “selected” and which is “comparison.” 50,000 means that Audience B overlaps with 50% of Audience A.

However, if Audience A becomes the selected audience that figure changes. Audience A only overlaps with 5% of Audience B. In practice, this means that the overlap between the two audiences is more likely to cause delivery problems for ad sets targeting Audience A than ad sets targeting Audience B. If you find that your audiences don’t overlap then that’s great. You won’t be saturating the same people with your advertising each time they are on Facebook, Instagram or WhatsApp.


If you find that more than 30% of your audiences overlap, then you’ve a problem. Over 30% means that the people in each audience list are too similar to each other. You’ll want to revise how you build one or more of the audiences. That way you’re going after a unique group of people each time you use an audience list in a campaign. You can consolidate audiences and their budget if they are very similar to each other. The other option is to refine your audiences by using age, gender, and other targeting to make sure each audience is distinct from one another.

A good way to make sure you don’t have an overlap is by not putting three or more interest/ behaviour targeting parameters in a custom or saved audience. We often audit Facebook ad accounts for clients as a one off service. The one common thing we see are custom audience lists that have half a dozen or more targeting parameters. Please stop doing this as it ends up giving you an audience list that’s 15 million people in size. There are times when an audience list of 15 million people makes sense:

  1. You’ve a large budget and you’re doing branding
  2. You’ve selling a product that everyone and their dog wants

Otherwise an audience size of 15 million is unnecessary. Think of your audience size as the bullseye on a dartboard. You want to aim for the center with a tightly focused audience. The other exception is if you have a lot of small audiences that you need to consolidate to give you reach.

How To Pick A Good Audience

We think about who our ideal audience is by how they spend their time online. Through some of our ecommerce clients, we have found that interests are better than beviours, but its worth testing. If you’re not good at figuring out your audience. You’ve a few options:

  1. Look at audience insights in Facebook
  2. Look at Facebook Page data to see what other pages your community likes

Bonus Tip: Expanded Interests

Also, don’t have expanded audiences checked when you’re building out a campaign. You can find expanded audiences at the ad set level right under audience and above advanced settings. This is often self checked by Facebook. That is it for this week.


See you next time.