Why don’t my Facebook Ad and Google Analytics metrics don’t match up?

Updated: Jul 24, 2020


Perhaps you’ve asked this question. Perhaps you get asked this question?


It’s perhaps one of the largest bugbears of online marketers. Facebook are moving towards giving us a solution, with their new Attribution tool, but in the meantime, it is an issue that continues to exist.


In this article, we attempt to debunk exactly why this is, and to equip you to be able to answer this eternal question the next time you are asked it.


But before we start…

Please don’t shoot the messenger, but are you 100% sure that your Facebook pixel is installed and configured correctly? It sounds obvious, but this is always the first port of call, to ensure that all events and values are passing through to your Facebook ad account as expected.


The best way to check, is to install the Google Chrome Facebook Pixel Helper plugin. It’s a great time-saver and can flag up any errors instantly.


If you’re certain the pixel is firing correctly, and that your Google Analytics code is perfectly installed, then it’s time to dive into the eight reasons why your Facebook ads and Google Analytics metrics are not adding up.

1. Cookie/Ad Blockers

Let’s start with the basics. Quite simply, if someone is using a cookie or ad blocker on their web browser, then Google Analytics isn’t going to work in tracking their activity.


This will cause issues with the Facebook pixel not triggering, similarly, the Google Analytics cookie may be unable to fully load and track user activity (anonymously of course).


Whenever either of these gets blocked (and it can happen A LOT), then your stats are going to under-report based on what you might see in any internal metrics.

2. They both handle conversion attribution date differently

Central to everything that we cover here, is the sheer basic fact that both Facebook and Google attribution handle conversion dates differently. Of course they do, us marketers all hate an easy life.


How so?


Facebook’s conversion attribution

It’s important to note that Facebook reports conversions based on the time of the ad impression, and not the time of the conversion.


Imagine that someone has been served an ad on 23rd July. The person then makes a purchase on 27th July. Facebook will attribute this purchase in it’s reporting to 23rd July — the date that the ad was served.


With this in mind, it is worth noting that anytime you pull stats from Facebook for a certain date or period less than 28 days ago, the data is likely to continue to change overtime. No, it’s not magic. As more and more people convert, up to 28 days since the ad click, the data is going to change for the date of the impression. Not everyone will purchase the very same day that they clicked an ad. Hey, but this is a good thing — it means you’re getting conversions further down the line. It also indicates that there is a consideration period for purchasers of your products. Useful stuff.


Google Analytics conversion attribution On the flip side of the frustrating attribution conundrum, Google Analytics handles conversions differently.


Consider the same Facebook campaign above. Where the person made a purchase on 27th July, Google Analytics would attribute this conversion to that date — 27th July (i.e. the day of the purchase, and not the day the ad was served).


Utm tags can help with your tracking to an extent, however are not a fool-proof method. You will still run into the issues that we cover in the remainder of this article.



Google have plenty of guides on using utm tags. In a nutshell, they are tags that you append to the end of a url, which enable you to track back the channel, audience and even ad content that people arrived and converted on your website via.


Key takeaway

When you are comparing your stats, always be aware of the attribution model used.


3. They both handle click attribution differently

Google Analytics is not alone in that it attributes conversions to the last click.


Take for instance, someone that clicks a Facebook ad, but doesn’t purchase. They then later see a Google Ads ad when searching on Google, and click to the website once again.


Except this time, they purchase.


With this in mind, although it was the Facebook ad that made the person aware of the product, Google Analytics would assign attribution to Google Ads, and attribute nothing to Facebook. Facebook on the other hand, would attribute the conversion to the campaign that delivered the result.


Anytime you are running a multi-channel campaign (Facebook, Google Ads, Twitter, Pinterest, Snapchat etc), whichever channel receives the last click (and the user then converts), that is the one that will get the attribution in Google Analytics. Whereas in Facebook, regardless of whether they viewed or clicked the ad, you will see the conversion.


Key takeaway

Brands increasingly should appreciate the “halo effect” of running paid social ads. They are part of the whole pie, and contribute to not just getting you conversions, but also exploding the awareness of your brand to people that have never heard about you before. There is no other advertising channel like it. Whereas Google Ads is primarily more intent based advertising, Facebook and Instagram ads are designed to interrupt the news feed and convince users that yours is a product they need.


It can be argued that adopting a 360 view to your marketing is the way forward. Research shows that consumers require seven to eight “touches” before they convert. Therefore, accepting that every channel that “touches” them contributes to getting the sale will give you a holistic picture by looking at your overall metrics in Google Analytics. The likelihood is that the more you spend across all channels, the more your revenue will increase.

4. They both track differently — people vs cookies

This is what we call people based tracking vs cookie tracking.


The great thing with Facebook advertising is that they are able to attribute actions to users, rather than cookies. For that reason, Facebook can track across different browsers, and different devices (as long as the user is signed into Facebook) — they know when and how users are logged into Facebook.


Conversely, Google Analytics doesn’t strictly have user profiles it can track — instead, they use cookie tracking. With Google, all tracking happens in the same browser that the cookie was dropped into. If someone browses the same website from their mobile and desktop on the same day, Google Analytics will view them as two separate people. Facebook on the other hand, would know they were the same person.


So if someone sees an ad at work in their Facebook news feed but doesn’t click, then later when they get home they decide to visit the advertiser’s website on their iMac, and purchases the product, Facebook is able to attribute this purchase to the ad the person saw (as long as they are logged into Facebook on both devices). Whereas, Google Analytics is unable to make this distinction, since the browser that the cookie was dropped into wasn’t the same one that the conversion occurred on.


Furthermore, this cross-device tracking is crucial in today’s super-connected world. Mobile is so entrenched in our daily lives, that it is always going to play a part in our purchasing habits, particularly in the research/consideration stage. The actual conversion on the other hand may happen when we are on our computers at lunch time, or at home on desktop when we have time think about it. According to Facebook, more than 65% of conversions start on one device and are completed on another. I too have seen several eCommerce clients with upwards of 40% of their conversions being cross-device. So with this in mind, Facebook reporting is going to be more representative of the conversions you get from your Facebook ad campaigns. Google Analytics just isn’t going to capture these.



“According to Google, consumers tend to browse and perform pre-conversion research on mobile devices but are not ready to convert, whereas desktop visitors are already informed and ready to convert. Consumers may perform micro-conversion actions, such as email sign-ups on mobile devices, but tend to ultimately perform that final conversion action on a desktop computer.” — https://www.marketing-mojo.com/blog/why-should-you-pay-attention-to-cross-device-conversions

4. They both handle view-through conversions differently

We earlier covered last click attribution, which essentially means that someone needs to actually click an ad for the conversion to be captured in Google Analytics.


But consider a user that sees an ad in their Facebook timeline, but doesn’t click it. They then go straight to the businesses website, and manually type in the domain name. They then purchase. Google Analytics would view this as an organic referral, whereas Facebook know that the person saw an ad, and therefore attributes the conversion to it. Their view is that Facebook has contributed to the sale in some way, through the user’s awareness of the product.


Taking this a step further — imagine a user has been retargeted with a Dynamic Product Ad campaign. This ad format is displaying them an ad for something they already have an interest in, and had previously added to cart. They do not click, but instead go straight to their Basket on the website and complete the transaction. This of course would make sense that they would do that, as they have no reason to click the ad, and are already very much product aware. The ad alone has reminded them that they had previously added a product to their basket, but not yet purchased it. Therefore, the Facebook ad should by rights take credit for having reminded them.


As Google Analytics has no insight as to which ads someone has viewed on Facebook, they are unable to report on view-through conversions. Only clicks. Therefore, Facebook is usually going to report higher metrics, for this very reason. But this isn’t a case of conversions being over-inflated. It can be argued that by viewing an ad in your Facebook news feed, regardless of whether you clicked it, you have been made aware of the brand, and therefore Facebook has had some influence in the purchase decision.


Of course, it is impossible to analyse exactly how much influence the ad had on the purchase decision!

5. Attribution window

Facebook reports on a 1-day view through and 28-day click through attribution window. Most 3rd parties track only on a click through window, which causes discrepancies because as mentioned above, Facebook also counts the view through.


So before you pull together any reports, make sure that the conversion attribution windows match for both platforms. By default, Facebook conversion reports are set to a 1 day view or 28 day click window. Google Analytics has a default 30 day window.

6. Moving from HTTPS to HTTP

Google Analytics gets referral information from the website HTTP header, and uses these to credit conversions back to ads. However, if there isn’t one present, it will treat such referrals as direct. Without a referrer field, Google Analytics doesn’t know where someone has come from.


In addition, whenever someone moves from HTTPS to HTTP, the referrer cannot be recorded. So if a website doesn’t have a secure version (i.e. https), then the referrer may be lost. This can result in third party trackers under-reporting Facebook conversions by as much as 40%.

7. Site visit limits

Google Analytics limits a site visit to once every 30 minutes per unique visitor. This is in order to prevent spam visits being tracked. However, this also doesn’t take into account any users that leave and return to the website within that time-frame.


Facebook on the other hand doesn’t have this kind of limit, and can report on multiple visits per unique user within the 30 minute timeframe.


So for a user that clicked to your website multiple times in a 30 minute period, Facebook would count this as multiple clicks, whereas Google Analytics would see this as a single visit.


Summing up…

It’s clear that there is no uniform manner in which 3rd party trackers and ad networks track activity. Primarily this is down to the data they have available to them, and the manner in which they are able to track people online. Facebook on the one hand has the benefit of knowing exactly who a user is and what their Facebook id is, and therefore can track cross-device conversions. While Google Analytics is limited to relying on cookie data.


Ideally, you will have internal data that you are able to use to match up your conversions, and attribute referrals where you can. If this isn’t possible, then choose the attribution model that works best for you. If you are confident that Facebook view-throughs contribute to your conversions, then this is a good measure. Keep an eye on the difference between purely clicks driven conversions versus including view-throughs, and see how much of an impact this has.

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