One of the key questions we seek to answer when implementing web analytics measurement is “Where is my traffic coming from?” While Google Analytics 4 (GA4) has some built-in functionality to automatically capture information about the source of traffic, marketers can proactively customize the way that traffic is attributed and categorized by appending UTM parameters to their link URLs.
What Are UTM Parameters?
UTM parameters (UTMs, for short) are bits of code that can be added to link URLs to convey information to GA4 about the origin of that traffic. UTM codes consist of a collection of parameters and their corresponding values. GA4 currently recognizes the following UTM parameters and surfaces their corresponding values in reporting:
| Parameter | Description | Examples |
|---|---|---|
| utm_source | referring source | |
| utm_medium | marketing medium | Email, cpc |
| utm_campaign | campaign name | spring_sale |
| utm_source_platform | advertising platform | DV360 |
| utm_term | paid keyword | swimsuit |
| utm_content | used to differentiate creatives | creative_1 |
By manually tagging your campaign or referral links with UTMs, you tell GA4 exactly how you want that traffic classified. GA4 is then able to surface those values in reports, allowing you to analyze traffic sources, side-by-side.
Note: GA4 does not require that all UTM parameters be used in campaign links, but the accuracy and utility of your reporting will reflect the completeness and consistency of your manual tagging. It is recommended that utm_source, utm_medium, and utm_campaign are all utilized in any campaign link that uses UTMs.
An Example:
AdForward, an advertising agency, has collaborated with your e-commerce company to launch an email campaign for your upcoming spring sale. A call-to-action link in the email ad will point to your homepage, located at https://www.ecommerce-biz.com/. To measure traffic originating from this campaign, you will need to manually append UTMs to the URL. After referencing your company’s campaign naming conventions document, you use the GA4 URL builder and get the following result:
https://www.ecommerce-biz.com/?utm_source=AdForward&utm_medium=Email&utm_campaign=spring_sale
When a user clicks on this link, GA4 will parse the UTMs and attribute the traffic to the appropriate source, medium, and campaign.
Key components of a URL with UTM Parameters:
Here’s the URL from the example marked up to demonstrate the formatting necessary for the UTMs to function properly:
Note: UTMs are codes and, as such, will only function when implemented correctly. Typos, improper formatting and/or use of non-standard parameter names will result in missing or inconsistent data. Tools like the GA4 Campaign URL Builder can be used to ensure proper formatting.
Finding UTM Data in GA4:
In the GA4 interface, the following dimensions are populated with values from UTMs in your URLs:
| UTM Parameter | GA4 Dimensions |
|---|---|
| utm_source | Session source, Session manual source, Source, Manual source, First user source, First user manual source |
| utm_medium | Session medium, Session manual medium, Medium, Manual medium, First user medium, First user manual medium |
| utm_campaign | Session campaign, Session manual campaign name, Campaign, Manual campaign name, First user campaign, First user manual campaign name |
| utm_source_platform | Session source platform, Session manual source platform, Source platform, Manual source platform, First user source platform, First user manual source platform |
| utm_term | Session manual term, Manual term, First user manual term |
| utm_content | Session manual ad content, Manual ad content, First user manual ad content |
Note 1: In the above table, dimensions with “manual” in the name always get their values from UTMs, whereas dimensions without “manual” in the name get their values from auto-tagging (where applicable) and then from UTMs (where auto-tagging is not applicable). Reference Google’s Traffic-source Dimension documentation for further info.
Note 2: In the above table, the scoping of the GA4 dimensions is a topic worthy of its own article. For our purposes, it is sufficient to note that dimensions with “session” in the name are session-scoped; dimensions with “first user” in the name are user-scoped; and dimensions that have neither of those in the name are event-scoped (for key events only). Reference helpful documentation on Google’s traffic source scopes for further info.
Best Practices
- Create and maintain a campaign naming convention document that anyone creating campaigns or tagging links can reference. Consistency in naming (including formatting, capitalization, etc.) is key to having accurate and useful reporting in GA4. Concise, clear naming makes it easier to avoid errors and inconsistencies.
- All inbound links should be tagged with UTMs; do not tag internal links with UTMs.
- Configure a custom channel group in GA4’s admin settings to aggregate traffic into high-level groups with rules based on traffic dimensions.
- When using linked advertising platforms, information from auto-tagging and information from UTMs may be commingled in reporting. In these situations, it is particularly important to use consistent naming conventions for campaigns in both the linked platforms and in your UTM-appended URLs.
- Use GA4 Explore reports to ensure traffic dimensions are being populated with the expected values, and to troubleshoot any issues.
