Facebook Interests vs Lookalikes, Which One Should You Use?

In the realm of Facebook advertising there’s an ongoing debate on the best way to target audiences. Everyone agrees that targeting is one of the most important elements of running succesful ad campaigns, but…

Should you use Facebook interests vs lookalikes? Which works best? Is Facebook’s AI smarter than you and better capable of finding the right people? Or are you better off choosing the interest to target yourself?

Let me start by saying that you don’t have to pick just one.

Although I sell software that reveals hidden Facebook interests, I also use lookalike audiences when targeting my ads. There are many considerations for using Facebook interests vs Facebook lookalike audiences.

In this article I’ll share these considerations.

Facebook Interests

Facebook interests are the longest existing method for targeting on the ad platform. Facebook allows you to input interest keywords to target an audience of people specifically interested in a topic.

facebook interests targeting

Next to being a social media platform, Facebook has increasingly become a big data company. They know a scary lot about their users, based on profile information and behavior they track on their own platform as well as through the Facebook pixel on millions of 3rd-party websites.

Facebook is pretty good at assuming what people are interested in.

But you also have to consider that they make money from advertisers that pay per impression. So it’s in their best interest to show your ads as many times as possible, which implies they prefer broad target audiences.

To determine interests Facebook uses user-defined profile information. But it also assumes certain interests based on behavior = not always correct.

I’ve written a separate article on how Facebook actually determines interests so that’s a recommended read if you’re interested to learn more.

Considerations When Using Facebook Interests For Ad Targeting

Facebook interests are the right choice for you if you’re just starting out with a new ad account or campaign. Or in general when you don’t have a lot of historic data tracked on your Facebook pixel.

So the first consideration is:

Do You Track Enough Data To Feed Facebook’s AI?

For Facebook’s optimization AI to effectively do its job, it needs data. And preferably a lot of it. That’s something most smaller advertisers don’t have.

If you want a Facebook campaign to exit the “learning phase” and be fully optimised, you need at least 50 conversions per week per ad set.

That’s a lot, if you optimise a campaign towards conversions.

When you don’t match this data requirement, you should consider using Facebook interest targeting and specifically pin-point your target audience.

You can’t fully rely on Facebook’s AI to find your perfect customers if you don’t feed it the data it needs to do that.

Because then it’ll just best shit in… shit out.

shit in shit out

Does Your Target Audience Share Common Interests?

A second consideration when using Facebook interest targeting, is if your target audience can actually be defined based on their (common) interests.

Because that really depends on the audience you’re going after.

Let’s for example say that you own a store that sells fishing equipment.

Your target audience are people who are really into fishing and willing to spend money on their hobby.

Your audience can be clearly defined by their common interests. They’re all enthusiastic about fishing and probably this hobby is reflected in their interests on Facebook.

They follow fishing Facebook pages, they share content related to fishing and they like photos of each others latest catch.

The same applies for most hobbies, passions, beloved pets, etc.

But let’s now look a different example.

Imagine you’re a realtor trying to reach an audience of people looking to sell their home. That’s a different story.

In this example your audience can’t be clearly defined by their common interests. Because most home owners in your area might be interested in selling their property at some point in time.

These people don’t share interests that clearly define them as “being interested in selling a home”.

The same applies for most goods and services that are tied to a specific point in time (repairs for example). People might be the audience for a car repair, but they definitely don’t share a common interest in “fixing cars”.

If you’d like to learn more about picking the right Facebook interests using what I call the “but nobody else criterion“, I recommend to read the 2nd chapter of my in-depth guide on Facebook interest targeting.

Facebook Lookalikes

When the Facebook ad platform opened up to advertisers, they just offered interests as a targeting method. But as the platform matured and Facebook started to learn more and more about their users, they launched lookalike audiences as another method for targeting Facebook ads.

Lookalike audiences are created by Facebook based on a “seed” or “source” audience you define and its goal is to find more people who are similar to your seed audience. To do that Facebook analyses the commonolaties in your seed audience and then goes out to find more people like that.

As mentioned before it needs good data to do that effectively, both when it comes to the volume and recency of the data as well as the quality.

Again, Do You Track Enough Data To Feed Facebook’s AI?

When instructing Facebook to create a lookalike audience, you’ll have to define a “source” or “seed” audience first.

This can be a custom audience that you’ve created from data your pixel or app has tracked. Or you can use a Facebook platform audience as seed, like the people who like your Facebook page.

Whatever audience it is, the seed audience should have a least 100 people from the country that you also want the lookalikes to come from.

While 100 is the minimum, Facebook recommends a seed of 1000 to 50.000 people. More is better, because that makes it easier for Facebook to find defining commonalities in the seed audience.

Considering data quality, the seed audience should preferably contain just your best customers (based on the recency, frequency and monetary value of their purchases). Facebook calls this value-based lookalike audiences.

Obviously a seed audience of high-value customers will result in much better lookalike audiences, compared to a seed audience of everyone who visited your website in the past 180 days.

But most smaller advertisers, don’t have thousands of high-value customers… so they often choose to use lower-value seed audiences.

If you’d like to use Facebook lookalike audiences but you are just starting out or have a small budget, I recommend to check out my review of Khalid Hamadeh’s Facebook course. Khalid is an ex-Facebook employee that teaches the “cascading lookalikes” strategy for this specific situation.

Is The Population Size Of Your Target Country Large Enough To Create A Targeted Lookalike Audience?

When you’ve selected a seed audience that Facebook should use to create your lookalikes from, you should also define the country the lookalikes should come from. As well as a % of that countries total population.

Selecting a higher % will create a larger audience, but it also reduces the level of similarity between that audience and your seed audience.

If you’re just starting out using lookalike audiences, it’s recommended to stick with just 1% of the population. Then Facebook will create an audience of 1% people that “look most like” your seed audience.

But, when you want your lookalikes to come from a country with a small total population, selecting 1% might result in a very small audience.

Monaco has a total of just over 37,000 inhabitants. So if you’re trying to create a lookalike audience of the 1% most similar to your seed audience, that’s just an audience of 370 people.

Assuming all of them are on Facebook…

While the US has a population of close to 330 million people. So a 1% lookalike audience still results in an audience of 2-3 million people.

Conclusion: Should You Use Facebook Interests Or Lookalikes For Targeting?

It depends.

That might not be the decisive answer you were looking for, but it’s the truth. In this article I’ve shared some considerations when choosing one or the other. But luckily you don’t have to pick just one.

In my own Facebook ad account, I have 2 acquisition campaigns.

In one of these campaigns I just create ad sets that target “stacked” and “layered” interests (learn more about these 2 methods in my Definitive Guide On Facebook Interest Targeting).

In the other I just create ad sets that target lookalike audiences. Personally I just use lookalikes from the highest value seed audience (thousands of my customers). Additionally I exclusively create lookalikes from a US-based audience, because that’s where the majority of my customers are from.

If your Facebook ad account is less matured and you don’t have thousands of customers (yet) to use as a high-quality seed audience, I recommend to use the “cascading lookalikes strategy” explained in Khalid Hamadeh’s Facebook ads course or use interest-based targeting instead.