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Facebook Attribution vs Google Analytics demystified (Attribution formula included)

It’s often the case that Facebook advertisers complain about the difference between what they see in Google Analytics and Facebook Ads manager. Facebook attribution shows much better results in campaigns than GA. Google Analytics reports a lower number of transactions and revenue coming from social.

Google Analytics and Facebook Pixel will always be different because they are collecting data in different ways. The fact that they’re different doesn’t mean that one is wrong, necessarily. You shouldn’t dismiss pixel data from Facebook because it doesn’t match GA 1 to 1 match. It never will. In this article, I will answer how each one works, in which points they differ and moreover, our closest source of truth including formula to demystify this mystery.

Let’s deep dive In!

People-ased tracking vs. Cookie-based tracking (Facebook Analytics vs. Google Analytics)

Facebook Analytics and Google Analytics sessions are identical if they are set correctly within the tagging system. The problem pops up when it comes to campaign attribution and campaign conversions.

Conversions on both platforms have the same trigger, but they are recorded differently. Some of the conversions you see on the Facebook platform are shown in Google Analytics, but they are processed as if they are coming from other sources. As a result, you do not see the same numbers on these platforms.

To figure out our truth-source formula, first, we need to understand how conversions are being tracked.

How does Google Analytics Attribution work?

Last click attribution

How does Facebook Attribution work?

  • User-based reporting (Based on User ID from Facebook)
  • 28-days click & 1-day view lookback conversion window

How Google Analytics and Facebook Pixel See Conversions

Google Analytics cannot keep track of two essential things:

  • Cross-device conversions (GA doesn’t work best in most cases – it has a problem identifying the same user if the user is not signed in chrome browser)
  • Google Analytics doesn’t recognize or track Facebook’s impression-based conversion

On the other side, why doesn’t the attribution data on Facebook match the data sources in Google Analytics?

Facebook is not a multichannel platform. Facebook’s campaign, attribution, does not consider other channels. Looking back for 28 days click & 1-day view attribution modeling, a purchase is always attributed to the Facebook campaign. Even if the user had more marketing touchpoints on other channels leading to final conversion, Facebook attributed it to itself.

When can you expect a conversion data discrepancy?

The essential use case for attribution is to figure out where to allocate your advertising budgets. Here are some of the most common data discrepancy cases:

Cross-device conversion discrepancy

In the customer purchase journey below, a customer initially sees an ad on Facebook mobile, clicks, but decides he’s still not ready to purchase. Then the next day, while at his laptop, he changes his mind when he clicks the ad on Google and purchases the item. Who should get the credit for this purchase? In comes the attribution modeling. According to Facebook – since he has interacted with the FB ad, users’ decision to purchase is attributed to Facebook. According to Google Analytics – the user clicked on Google Ads, so it’s a clear case of Google Paid Conversion.

View conversion discrepancy

The following case is an even more common problem in attribution modeling.

Our user first sees an ad on Facebook (any device) but continues scrolling through News Feed without clicking on the shown ad. The same day, inspired by that exact Ad he saw our user opens his browser on mobile, types the exact URL address, and makes a purchase. Who should get the credit for this purchase? According to Facebook – view through conversion FB – impression-based – conversion is attributed to Facebook. According to Google Analytics – it’s direct traffic conversion, no Facebook at all.

There are a bunch of other cases of how Facebook Attribution vs. Google Analytics could differ. Data discrepancy occurs in the mingling between two big competitors – Facebook and Google.

The closest Facebook Attribution vs. Google Analytics single source of truth Formula

For your team, it would be good to have a “single source of truth” for purchase data, especially if you’re reporting on a last-click basis. To get the numbers closer to each other, you could try tracking click conversions from Facebook and disregard view-through conversions, which are not 100% accurate. You can adjust the Facebook attribution in the ‘customize conversions column’ menu of Business Manager so that it only shows conversion clicks. That is the first step in acquiring your formula.

Campaign attribution
Focus your attribution windows on clicks

Also, you can consider counting assisted conversions from Google Analytics multichannel conversion report.

Dashboard Facebook attribution
Estimate yours Google Assisted conversions value

The formula applies to you if your no.1 advertising channel is Facebook. Our simple attribution formula – not applicable for every case*

Formula attribution
“Single source of truth” for purchase data, if you are into Facebook Ads

Above is a simplified formula, not a scientific one. Depending on your niche, you should adjust variables. Assisted conversion value and View conversion value in this formula are calculated depending on how complicated your conversion process is. This formula is the simple and easiest plug-and-play way of measuring attribution.

The more complicated the conversion process, the higher the chances for data discrepancy are. The user will interrupt his conversion process and continue to purchase from another device. Go in your Google Analytics/Business Manager and estimate variable values based on the number of steps in your process from adding to cart up to the purchase itself.

What about campaign optimization?

Be sure to look at numbers from two different perspectives. Look in Google Analytics to have an accurate picture of the total revenue driven from all sources. Use that data as your overall source of truth for purchases and on-site analytics.

Optimize for the channel on which you advertise. Optimize against Facebook data if you have fewer effective marketing channels. If your business relies mostly on awesome Facebook ads, optimize for Facebook.

GA vs. FB: take-aways

Facebook marketers must understand differences in Facebook vs. Google analytics data to attribute creative, set audience targeting, and drive conversions adequately.

Data is collected differently, but that doesn’t make it “wrong.” I would suggest using Google analytics attribution as a source of truth for on-site and conversion data but use Facebook conversion data for optimizations and take it into account for broader reporting and attribution.

Bonus GA Template

Use and take ownership of our reporting dashboard integrated with Google Analytics to report on the performance of your e-commerce efforts. It’s a 5-minute process if you are familiar with Google Analytics and your tracking is defined. Format: Google Sheet template

Frequently Asked Questions

1. How to set up facebook attribution?

Facebook Pixel is a piece of code that you can implement on your site to track conversions such as any purchase completed or subscription sign-up.

Once the code has been embedded on your website's page or landing page where the goal took place (i.e. "thank you" page), each time this goal takes place within those pages, data will be collected by Facebook analytics servers and will follow these events as far back as when the pixel was put in place.

2. What is Facebook attribution?

Facebook attribution enables you to measure the incremental impact of all your marketing efforts— Facebook, on your conversions. Attribution lets you understand how well certain parts of your funnel are working so that you can improve things like your landing pages or product pricing along those weak points.

3. How to use Facebook attribution?

To access the Attribution tool, head over to Ads Manager and select Attribution.

When attributing a conversion for an ad campaign in Facebook, there are three options available:

- Device Begins Conversion

- Browser Begins Conversion

- View Content Conversions