First, what it is: a metric in the ads reporting tool that takes into account positive and negative feedback from the target audience. Facebook scores the ads between 1 and 10, 10 being the highest and in this case most relevant.
Facebook states that Relevance Score should not be used as the primary indicator of an ad’s performance, and I agree. While it is a good high-level metric, is not the end-all and be-all number.
I have some ad campaigns that are showing a relevance score or 2 out of 10 that are hitting CPA goals consistently. And on the flip side, I have ads that have a score of 10 that are not profitable.
Facebook takes into account positive feedback in the ads, such as likes and shares. The campaign in my 1st example is a niche product that doesn’t receive much engagement in the ads to begin with. No engagement (positive feedback) in combination with any sort of negative feedback, such as hiding the ad, will cause the score to plummet. Yet all the while, the ad is hitting the CPA targets.
In the 2nd example, I am in an engaged target with very strict CPA goals. My ads in this case receive decent engagement and actions to counter some of the negative feedback to keep my score high.
This screenshot shows the performance of an ad that had “high” positive feedback to counter the “high” negative feedback, and it also takes into account the other ads shown to my audience to give me a score of 10. Yet, with the target being competitive, these highly relevant ads need to be paused because the CPA is above my target goal.
The upshot is that Relevance Score is an indicator of relevance, a sort of a nice-to-note metric that is by no means the final indicator of how an ad will perform with the metrics that matter to your budget.