UTM Codes: The Pros and Cons
Even using UTM codes, not all traffic that the digital ad campaign drives to your website will appear in their Google Analytics. Why?
Users might have set their browser preferences in ways that prevent Analytics used on websites from collecting data.
Google uses bots to audit and click on ads (mostly in their hubs, like California) to test ads before they go live. UTM codes pick up on this, and often you get several UTM clicks from this state throughout the duration of the campaign, with a 100% bounce rate and zero seconds on the site. Sunnyvale and San Francisco are the two biggest auditing sites, which you can see in your Google Analytics Channels report.
If a user comes to your site from an ad, and then leaves the landing page before the tracking code executes, then the code is never passed to the Google servers, and that click is not registered as a Session. This is called Server Latency and may be an issue with the advertiser’s website loading speed.
Google Analytics also has limitations when it comes to correctly “sourcing” where traffic comes from. For example, Google Analytics may list mobile app traffic (traffic coming from ads people see on their mobile devices) as DIRECT rather than REFERRAL (read more on this above).
Some browsers give users the option to disable images that are requested from domains other than the current page. Disabling such images will prevent data from being sent to Google Analytics.
A visitor may click on your ad, but then change his/her mind and prevent the page from fully loading. This can happen by clicking to another page or by pressing the browser’s stop or back buttons. In this case, the UTM code doesn’t fire and Google Analytics doesn’t register a visit, but the ad server still counts this as a click.
App traffic in general is very hard to track in Google Analytics even with UTM codes. When someone sees the mobile ad inside an app (and most mobile inventory is in apps) and then clicks to the advertiser’s website the app may not pass the tracking code to Google Analytics. In addition Google Analytics categorizes it as a bounce because it can’t track that person who comes from an app. It’s a limitation of Google Analytics. An app is not a web site, it is not viewed in a web browser and they do not contain header information when linking out to a website so Google Analytics sees there is no referrer in the headers. So when Google Analytics is seeing the user visiting your website, it is seeing that there is no referral and it will deem the traffic to have no source and therefore assign that referral as Direct traffic and as an immediate “bounce”.