Data Collection, Data Quality

Which Ad Blockers are blocking Google Analytics?

Ad blocking software has gotten a lot of attention recently. Not because it’s new, but likely because it’s being used more widely. Studies put the ad block penetration at up to 37% or even higher – it depends on country and other factors. Ad blockers are intended to block those annoying (remarketing) ads that follow you around the net. But are ad blockers also affecting our ability to collect traffic data, e.g. by blocking Google Analytics?

The short answer is “yes”. Ad blockers can and will block Google Analytics. And if a user blocks Google Analytics, then that user is not being tracked. Nothing is sent to Google Analytics servers, and you’re left with incomplete data.

But how serious a problem is it? Well, to my knowledge there’s no studies on that. You could measure it though. I wrote a post some time ago on how to track if Google Analytics is blocked. Using that approach, I found that around 10% of users on one of my websites are actively blocking Google Analytics.

Now, I can’t measure how they’re blocking Analytics. But it got me thinking about ad blockers. The blockers I’ve tried usually have some customisation options allowing you to block all kinds of things – either via lists made by others or by entering URLs (e.g. google-analytics.com). So I wanted to find out which ad blockers can be used to block Google Analytics – and which ad blockers that do it by default.

Therefore, I picked out some (not all) of the popular free ad blockers. I basically installed them and checked if they blocked Google Analytics by default. If not, I also checked whether or not the blocker could be configured to block Analytics manually. The result is the list below:

Ad Blocker Users   Is GA allowed by default? Is GA blocking customisable?
AdBlock +10,000K
AdBlock Plus +10,000K
AdBlock Pro ~2,600K
AdGuard AdBlocker ~1,800K
Ad Muncher #N/A
AdRemover ~1,000K
Ghostery ~2,400K
Simply Block Ads! ~158K
SuperBlock Adblocker ~13K
μ Adblock ~5K #N/A
μBlock Origin ~1,200K

So the good news are that most ad blockers will allow Google Analytics tracking by default. Well, at least the blockers I’ve tested in Google Chrome.

In addition, the bad news are that:

  1. Almost all ad blockers allow users to add Google Analytics to the block list. And some users will undoubtedly use that functionality.
  2. The two blockers I tested in Firefox and the one desktop ad blocker software I tested for Windows, all block Google Analytics by default!

As such, while most blockers will not actively block Google Analytics, almost all of them can be configured to do so. This definitely presents web analytics with challenges since we’re left with incomplete data.

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