10 Reasons Your Google Analytics Data Will Never 100% Match Your Other Data Sources

Google Analytics is a powerful tool providing more insights about what our users do online now more than ever. This with far more accuracy than was available for advertising in the pre-digital days. 

But high-accuracy is not perfection. 

Attaining highly-accurate, reliable data is very important for making business decisions. But rather than striving for perfect data, just knowing some of the limitations can help you use your data in a reliable way.

Why Google Analytics Data Doesn’t Match Google Ads, Facebook, or Other Data Sources

Here are 10 (uncontrollable) reasons your data is unlikely to perfectly match your other data sources, like Facebook, Google Ads, or your CRM:

Reason #1 - Ad Blockers/Tracking Blockers

The reality is an ever increasing number of people install ad blockers and tracking blockers because they don’t want to see ads or want more privacy. 

Even though your intentions with their data may be 100% above the board, people install ad/tracking blockers to protect themselves across the board.

That means your data will exclude users who have blockers installed. (Of course these aren’t the best people for you to be spending money on anyway.)

Reason #2 - Javascript Errors or Javascript Not Loading

Code breaks, sometimes we know why, but there’s many fringe cases we can’t track down. For example:

Someone is running an extension that interferes with your javascript tracking code. Your Google Analytics data might not fire but your server logs or other tracking systems still show someone interacting with your site.

Reason #3 - Page Timeouts/Tracking Doesn’t Load

Even the most optimized site may have the occasional slow load issue on some of your users browsers. 

  • Consider the fastest site sometimes won’t load if your wifi gets spotty. 
  • Sometimes servers have issues as well and may not serve all or complete files. 

In these situations a page may load or partially load without your tracking loading.

Reason #4 - Your Tracking Fires, Even if Your Backend System Errors

You clicked confirm purchase, you thought it went through, but then after a few seconds you get an error telling you it didn’t go through. 

Your back end system knows better, but depending on your analytics tracking, it may have fired as a successful purchase anyway. 

This is one that can sometimes be mitigated by waiting for your back end system to confirm before you fire the tracking.

Reason #5 - Cookies are Great, Until They're Cleared (or Browsing Privately)

Cookies help us identify returning users and behavior over time, but sometimes people clear their cookies. 

Some people clear their cookies religiously or even disable many of them, while others may never think of it until they have a problem and a troubleshooting page tells them to clear their browser cookies. 

Regardless, you can count on most of your users clearing their cookies at some point and we can’t know when.

Reason #6 - Users Have Multiple Devices (and Browsers)

User-ID views can help you see the same user across devices -- if they log in.

Google has calculation methods to more efficiently count users, but even this still has an error rate. 

Reason #7 - Bots, Bots, Bots ... and Spam

Bots and spam are inescapable. 

We can mitigate with Google’s bots filters and manual filters. Servers have different methods of blocking bots. Some spam bypasses your website and goes straight to Google Analytics. 

There’s a slew of methods we can use to reduce fake traffic, but this is a constant whack-a-mole situation so you’ll never get this out of your data completely.

Reason #8 - Different Tools, Different Methodologies

Google Ads, Facebook Ads, Adobe Analytics, Google Analytics, all the various tools you might be using to gather data have slightly (and sometimes majorly) different methodologies for tracking and attribution. 

Also, if you’re running more than one of these on your site, there’s also the possibility that one of their tags may occasionally fail (see Reason #2).

Reason #9 - Your Dev Team is Testing Your Site

Site testing is a common (and important) task but making sure testing doesn’t hit Google Analytics may not be top of mind for your developers. Hopefully you are pretty good about making sure you don’t have a real $500 purchase hit the site when testing, but there are some things we can do to mitigate blocking that testing traffic with filters or tracking blockers, but it’s unlikely you’ll catch all.

Reason #10 - Your Campaign Parameters are Being Stripped

Hopefully you have a robust campaign tracking plan and are on top of tagging every link you send out into the wild. But hey, stuff happens. 

People take the campaign parameters off your links. Third party sites or redirects from an app to browser strip them. They may still show up as a click from another site, but when they make it to Google Analytics it’s (direct) / (none) but really Dark Traffic

So if it's Never Going to Match, Should I Trust My Data?

Yes! Perfect isn’t the goal. If you have 90-95% accuracy, you’ve got plenty of good data to work with. 

Simply being aware of the issues that may cause the discrepancy can help you interpret your data so it’s still usable and you can recognize where things may be suspect and where the direction is solid.

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Michelle Noonan
Michelle Noonan
Sr. Lead, Digital Measurement Solutions