Meta Conversion Events, Deduplication, and Conflicting Reporting

If you dig into your Meta conversion events, you are likely to notice a problem: Conversion event data doesn’t match up. Why?

I’m not talking about your event data matching up with Google Analytics or other third-party reporting tools (these things will never match up). I’m talking about Meta’s own conversion event data not matching up.

You may be surprised to know that this isn’t a bug or a problem. There is a reason for it. And once you understand that reason, your data will make a lot more sense.

Let’s clear this up…

The Conversion Data

First, let’s establish the various pools of conversion data that we’re concerned about here.

1. Standard and custom event data within the Data Sources section of Events Manager
2. Custom conversion mapped to that standard or custom event
3. Ads Manager conversion reporting

These three will almost never match up. For the most astute, it may be obvious why #3 doesn’t match up with #1 or #2.

But, do you understand why the first two won’t match up? The assumption tends to be that Events Manager is over-counting or the custom conversion is restricted by a rule.

That’s not the case…

About Event Deduplication

The primary reason for discrepancies between these three groups is right here: Event deduplication. But it’s not what most people think.

There are actually two different types of deduplication.

1. Browser vs. API Event Deduplication.

Event Deduplication

In this case, you pass events to Meta from both your browser (using the Meta pixel) and Conversions API. But when you do this, the same event will often get passed from both sources. Instead of counting that event twice, Meta will need to match them up to the same user and deduplicate the events.

This is what most advertisers think of when they hear about event deduplication. But there’s another…

2. Multiple Times From the Same Person.

Meta will also deduplicate events in another scenario.

Event Deduplication

The above passage comes from Meta’s documentation.

Let’s assume your pixel has sent multiple purchase events from the same person during a short period of time. This might happen if a user refreshes a confirmation page. Or it could happen if you use engagement-based events that can happen multiple times.

In some places, you will see raw event totals prior to deduplication. In others, the data will be cleaned up.

Now, let’s get to what you should expect to see in each of the three locations…

Events Manager Data

Events Manager Data Sources

The events data that you see in Events Manager is before processing and deduplication of events. It’s the raw total.

In the example above, the event is passed using both the pixel and API. The 80.2k number is likely closer to 40k after deduplicating the browser vs. API events. But it could be even lower than that (it will be) after removing the second form of deduplicated events.

Custom Conversion Mapped to an Event

I created a custom conversion mapped to that same event shown in Events Manager.

Custom Conversion Mapped to Custom Event

Remember that the original number prior to deduplication of any kind was 80.2k. Here, the total number of events is only 18.8k. Why?

Custom Conversion

You may guess that it’s due to the rule you need to create with custom conversions. It’s not. The rule used will pick up every event fired on the website.

It’s entirely due to deduplication. We can make a couple of logical assumptions…

1. After deduplicating browser and API events, the event total dropped from 80.2k to 40.1k (or so).
2. After deduplicating multiple events from the same user during a short period of time, the event total dropped from 40.1k to 18.8k.

You’re not going to typically see this rate of drop-off due to a user repeatedly performing the same event during a short period of time. But this event is unique in that it can happen many times (and often will).

Ads Manager Reporting

Ads Manager Reporting

Finally, we have Ads Manager reporting. When you add a column to your report for a specific event, it is very unlikely to match up to Events Manager data or custom conversion data.

The primary reason that it won’t match up with either is that Ads Manager reporting is only for those events that can be attributed to your ads. That’s most obvious.

But even if you are positive that your ads drove 100% of your conversions and they all happened within the Attribution Setting, Ads Manager reporting will be less than Events Manager because it’s after deduplication.

Ads Manager reporting and custom conversion reporting could conceivably be the same if all conversions came from your ads within the Attribution window since both numbers will be after deduplication.

Watch Video

I recorded a video about this, too…

Your Turn

What inconsistencies do you see with your data?

Let me know in the comments below!