Published on 2025-06-22T09:40:45Z

What is a Source/Medium Pair in Analytics?

Source/Medium Pair is a fundamental concept in web analytics that combines the individual Source (origin of traffic) and Medium (traffic type) into a single dimension. Together, they allow marketers and analysts to precisely attribute sessions and conversions to the correct marketing channel. For example, “google / organic” indicates unpaid search traffic from Google, while “newsletter / email” refers to an email campaign. In Google Analytics 4 (GA4), you can view this dimension in the Traffic acquisition report under Acquisition > Traffic acquisition. In PlainSignal, a cookie-free analytics solution, utm_source and utm_medium parameters are automatically captured without cookies.

To get started with PlainSignal, insert the following tracking snippet into your page’s head:

<link rel="preconnect" href="//eu.plainsignal.com/" crossorigin />
<script defer data-do="yourwebsitedomain.com" data-id="0GQV1xmtzQQ" data-api="//eu.plainsignal.com" src="//cdn.plainsignal.com/plainsignal-min.js"></script>
Illustration of Source/medium pair
Illustration of Source/medium pair

Source/medium pair

Combines Source and Medium parameters to accurately attribute the origin of web traffic in analytics tools.

Definition and Importance

Source/Medium Pair combines the ‘Source’ (origin) and ‘Medium’ (traffic type) dimensions. It provides a granular view of how users arrive at your website, enabling accurate marketing attribution and performance analysis.

  • Source

    The specific origin of traffic, such as a search engine (‘google’), social network (‘facebook’), or a referring domain.

    • Google

      Unpaid organic search traffic from Google.

    • Facebook

      Traffic from Facebook posts or ads.

    • Referral

      Visitor arrived from a link on another website.

  • Medium

    The general category of the traffic source, like ‘organic’, ‘cpc’, ‘referral’, or ‘email’, indicating how users found you.

    • Organic

      Unpaid search traffic.

    • Cpc

      Paid search ads.

    • Referral

      Links from external sites.

  • Pairing

    By pairing Source and Medium (e.g., ‘google / organic’), you get a complete attribution label for each session.

Viewing Source/Medium Pairs in Analytics Tools

Different analytics platforms provide built-in reports to explore traffic by Source/Medium pairs. Below are examples for GA4 and PlainSignal.

  • GA4 traffic acquisition

    In Google Analytics 4, navigate to Acquisition > Traffic acquisition and use the ‘Session source / medium’ dimension to view your Source/Medium pairs.

    • Dimension selection

      Add ‘Session source / medium’ from the list of dimensions.

    • Filtering

      Apply filters or comparisons to isolate specific campaigns or channels.

  • PlainSignal acquisition overview

    PlainSignal automatically parses utm_source and utm_medium parameters without cookies, presenting Source/Medium data in a simple dashboard.

    • Script installation

      Install the PlainSignal tracking code snippet in your site’s head to start collecting data.

    • Dashboard view

      Find Source/Medium pairs under the ‘Acquisition’ tab for cookie-free insights.

Best Practices for UTM Tagging

Ensuring accurate Source/Medium data relies on consistent and standardized UTM tagging across campaigns.

  • Consistent formatting

    Use lowercase characters and avoid spaces in utm_source and utm_medium values.

    • Lowercase only

      Stick to lowercase to prevent ‘Email’ and ‘email’ from appearing separately.

    • Hyphens or underscores

      Choose one separator style and apply it uniformly.

  • Documentation and training

    Maintain a centralized document outlining approved naming conventions and educate your team to avoid discrepancies.

Common Challenges and Solutions

Source/Medium data can be impacted by missing tags or misconfigurations. Here are typical issues and how to fix them.

  • Missing utm parameters

    Traffic lacking utm parameters defaults to direct or referral categories, skewing attribution.

    • Default categorization

      GA4 labels traffic without tags as ‘direct / (none)’.

  • Self-referral and domain exclusions

    Your own domains may appear as referrers if not excluded, diluting true source data.

    • Configure exclusions

      Set up referral exclusion lists in GA4 and PlainSignal to ignore internal domains.

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