Why FB sends more traffic to “bad” ads: FB Breakdown Effect explained


Facebook explains why you should wait before judging the performance of your campaigns. 2019 FB Ads benchmarks: Are you performing better or worse?

The Breakdown Effect

If you’ve heard of the FB Breakdown Effect, great! You know what we’re talking about here! However, if you’re like Henry Wang and you’re wondering what it is, well, just keep reading.

A common point of confusion is that Facebook’s system appears to shift impressions into underperforming ad sets, placements or ads.

But, in reality, the system is designed to give you the best results at the campaign level, based on the ad set optimization you choose.

Here’s the example that Facebook came up with to explain this effect:

Let’s say that you launch a conversion campaign. You have one creative asset and you pick two placements: Facebook Stories and Instagram Stories. The budget is $500 for the whole campaign with a single ad set.

In the beginning, the CPA on FB Stories is $0.35. While on IG Stories, it’s $0.72. However, as the campaign goes on, IG Stories receives more budget.

Have you experienced something similar?

At the end of the campaign, FB Stories spent $50, while IG Stories $450. Why?

“At the start of the campaign, the system began delivering ads to both platforms to explore where the lowest costs were. […] The system recognized that although Facebook Stories was driving the most efficient results initially, it predicted the cost was going to increase throughout the duration of the campaign.

Based on the anticipated rising costs, the system was able to pivot and shift the budget to Instagram Stories in order to drive a more efficient average CPA for the duration of the campaign.”

This is the reason we sometimes find that the reporting data doesn’t match up with our expectations.

FB knows how the costs will change during the campaign, and it shifts the budget accordingly.

And that’s the Breakdown Effect.

The lesson to learn? Don’t play about with your campaigns too much. It’s sad to say, but the FB ad platform is smarter than us mere humans.

So, it can predict how the campaign will run more accurately, and work accordingly to deliver the best final results.

This Breakdown Effect causes a lot of confusion among advertisers while they’re interpreting their Ads Manager statsIt might have happened to you as well.


Facebook run this campaign for me mem

So, remember that Facebook will always work in your favor and create flexible campaigns with the lowest CPAs.

That’s all. Hopefully, we eliminated some of your fears and doubts. However, if you want to dive deeper into the Breakdown Effect and satisfy your nerd side, here’s the detailed explanation by Facebook.

Facebook Ads 2019 Benchmarks for industry

Struggling to judge the performance of your KPIs? You should probably have a look at this Facebook Ads benchmark released by WordStream.

The Benchmarks report has been shared by Rutger Thole, and it was created by analyzing the data of all WordStream clients.

You can find the averages across 18 industries for various KPIs such as Average Click-Through Rate (CTR), Average Cost per Click (CPC), Average Conversion Rate (CVR), and Average Cost per Action (CPA).

You can find all the data here.

However, keep this in mind: The objective of your campaigns, the price range of your product or service and the audience and positioning will all influence the KPIs.

For example, a campaign with a conversion objective will have a higher CPC than a campaign with a traffic objective. Therefore, you should review the benchmarks accordingly.


  1. I’ve found it to be very strange, indeed. I’ve tested multiple ads over time, and ongoingly seen this effect, facebook sending traffic to lower performing ads.
    And it seems to be ongoing over longer term too.
    I’ve done some tests on purpose, and these are the ugly, home-made looking ads that FB are sending it to, as compared to the others which are based on the same message of the ugly control, but LOOk better and include emotional hooks and tested copy.. I seperated them out in different ad sets (to force delivery to the other ads), multiple times in multiple tests – and my ‘non ulgy’ ones that were improvement on the ugly control consistently outperformed, both in terms of CPC and tracked CR.
    Following these test, if I combine the Ads into one Ad Set, FB are still sending 98% of traffic (literally 4000 impressions vs 10) to the bad performing ad….
    My quality/engagement rating on the good ads also get graded as in top percentile as well, on these same campaigns!!

    I’ve repeated this at least 8 different times, diff ads and verticals, with same results.
    Based on my experience with media buying and other traffic networks (before i entered Facebook), upon testing it was obvious that they’d purposesly send some crap, just enought to ‘burn’ you while still giving you a chance’ to keep on spending your money with them (yeh, like a casino).

    At least I know how to control things, but I have no idea what it’s doing to the algorithm big picture.


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