Understanding Conversion Differences Between Google Analytics, Facebook, and AdWords

December 20, 2017

This is a guest post from Ashley Aptt, Account Director at 3Q Digital.

If you’re an advertiser and you’ve ever wondered why conversion metrics are different in AdWords and Facebook versus Google Analytics, you’re not alone. As a user goes through the purchase process, it’s likely that they’ll interact with the same brand numerous times before converting. Assuming there are no tracking issues on your site, these reporting differences can be summed up in one word: attribution.

What Is Attribution?

Attribution is the science of understanding which media campaigns are driving conversions for your business. It’s very common to see data discrepancies in Google Analytics compared to media platforms, and it all boils down to differences in attribution models.

Here’s a common path a customer may take along the purchase journey with one company. We’ll return to this scenario throughout the rest of this article.

  • Day 1: The user starts their search and clicks an AdWords ad
  • Day 2: The user sees a Facebook ad and clicks it
  • Day 2: The user clicks another AdWords ad
  • Day 3: The user later converts on a Google organic listing

In the use case above, Google Analytics would assign conversion credit to the Google organic listing, Google AdWords would take credit for the conversion, and Facebook would also take credit for the conversion. As you can see, both AdWords and Facebook take credit, but Google Analytics only considers the organic listing.


Let’s dive into the attribution differences between these platforms in greater detail.

Understanding the Google Analytics Attribution Model

Many platforms use a last-click attribution model. This means that the last ad or keyword that led to a conversion gets credit. Google AdWords, for example, uses a last-click attribution model (by default). So, when a user clicks two paid search ads, AdWords assigns conversion credit to the last ad that was clicked before the conversion event occurred.

Google Analytics also uses a last-click attribution model. But an important differentiator is that Google Analytics takes all channels into account. So, in the scenario above, even though Google AdWords is applying conversion credit to the last AdWords ad that was clicked, Google Analytics isn’t giving Google AdWords any credit for this conversion. Google Analytics attributes all conversion credit to the Google organic listing. This is a key difference in understanding why Google Analytics conversion data can differ greatly compared to media platforms.

How Does Time Impact Conversion Data Discrepancies?

Another key differentiator in how Google Analytics records conversions in comparison to many media platforms is that Google Analytics assigns conversion credit on the day of the conversion, whereas media platforms typically assign conversion credit on the day of the click.

Again, looking at the example above, Google Analytics records the conversion on Day 3 (the day of the purchase). Conversely, Facebook and AdWords retroactively assign conversion back to
Day 2 (the day each of these platforms received their last click).

Depending on your business, this difference can be meaningful, especially if your purchase cycle is longer or if you have an event that drives a lot of conversions on a given day.

More Ways Facebook Attribution Is Different from Google Analytics

In addition to the differences with last-click models and the timing of conversion reporting, a few additional elements make Facebook conversion tracking unique.

First, Facebook can track impression-based conversions. The default attribution window for Facebook is 28 days post-click and one day post-view. This means that Facebook counts a conversion even if a user never clicked a Facebook ad. This is a huge difference in reporting, because Google Analytics doesn’t have the ability to track impression-based conversions.

Another difference between Facebook and Google Analytics is that Facebook has the unique ability to track users from one device to another (if the user is signed-in on all their devices). This means that Facebook can track cross-device conversions. Google Analytics only uses cookies to track users, so it doesn’t have the ability to track cross-device conversions.


There are several reasons why conversion data in Google Analytics doesn’t match conversion data that media platforms provide. Neither method is right or wrong, but it’s important to understand what the attribution differences are, because these differences can cause a huge discrepancy in the data that you see reported in each platform, especially in Facebook.

If you don’t feel comfortable using Google Analytics data as the point of truth because it greatly under-values Facebook, but you also don’t like to use the Facebook data because it’s too lenient with the conversion data it records, then using a multi-touch attribution platform is likely your best option. Multi-touch attribution platforms can look at the various touchpoints in a user’s purchaser cycle and determine a better way to assign conversion credit to each platform.

Marin's TruePath

Want one place to track all your channel activity, including every touchpoint that led to a conversion? This is where Marin TruePath comes in—a lightweight, cross-device, cross-channel measurement solution. TruePath delivers user journey reports that properly attribute revenue to all touchpoints—including search, social, display, organic traffic, and more. To learn about TruePath, contact Marin today.

Ashley Aptt

3Q Digital
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