Having overlapping audiences is not necessarily a bad thing, but it can lead to poor delivery of your ad sets. This is because when ad sets from the same advertiser are going to end up in the same auction (meaning they're targeting similar audiences), we enter the one with the best performance history and prevent the others from competing to get shown. We do this so that your ads are not competing against each other, which can drive up costs and lead to inefficient uses of your budget. You can check if two audiences you're using are overlapping with our tool:

1. Go to your Audiences.
2. Tick the boxes next to the audiences you want to compare (up to five).
3. Click Actions > Show Audience Overlap.

Notes:

• 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 drop-down in the top right-hand corner of the tool. You can choose from any of the audiences you've 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 tool will show both the "Overlap" and the "% overlap of selected audience". The "Overlap" column shows the number of people who are in both audiences. The "% overlap of selected audience" column compares the number of people who are in both audiences to the total number of people in the selected audience to show the percentage of overlap. This column is why the selected audience is separate from the comparison audience. Here's an example to help explain:

Let's say that you have a selected audience with 1,000,000 people (we'll call this Audience A) and a comparison audience of 100,000,000 people (we'll call this Audience B), and that there are 800,000 people who are in both audiences. The number 800,000 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". 800,000 means that Audience B overlaps with 80% of Audience A. However, if Audience A becomes the selected audience, that figure changes. Audience A only overlaps with 8% 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 rather than ad sets targeting Audience B.

If audience overlap is causing you problems:

• Consolidate your overlapping ad sets. If some ad sets are targeting very similar audiences, you could see better results by consolidating them into one with a larger budget.
• Refine your targeting. Take advantage of location, age, gender, interest and/or behaviour-based targeting to ensure that each ad set has a specific and distinct audience. You can also try creating separate Custom Audiences (from a pixel or your customer data) or Lookalike Audiences (of people similar to your best customers) for each ad set.

Consolidation and refinement are opposite ways of solving the problem. (One makes an audience larger, the other makes an audience smaller.) The best choice is different for each situation. However, a useful idea to bear in mind when deciding is: If two audiences are distinct enough that you set different bids for ad sets targeting one compared to the other, try keeping them separate and refining them further. If not, try consolidating them and combining their budgets.

If you're still having trouble, take a look at this general troubleshooting guide.

If you're having trouble with this in relation to Lookalike Audiences, consider trying out the advanced options for Lookalike Audience creation.

* Nguồn: Facebook