Google Analytics Audit Test #

24

(not set) source

Why It Matters:

Critical to understanding where your traffic is coming from and assigning appropriate credit.

Industries:

All

Checks For:

Accuracy

How accurate is your recent data?

Insight Category:

Attribution

Can you tell which marketing efforts are working?

Google Analytics Audit logo

Background

A GA4 audit is essential for uncovering missing insights—key data points that organizations don't yet know and can act upon. A well-done audit evaluates both behavioral tracking and traffic attribution, ensuring each is accurate and useful. It also assesses whether the data collected truly supports business decisions and reporting.

Test Detail

This test identifies sessions where the traffic source is listed as (not set) in GA4.

The source dimension identifies where the traffic originated—Google, Facebook, Email Newsletter, etc.—and is critical for channel attribution, campaign performance, and media ROI.

When source is (not set):

  • The traffic cannot be attributed to any specific platform or referrer
  • GA4 reports lose transparency into acquisition effectiveness
  • You may under-credit certain campaigns or traffic channels
  • Audience building and funnel optimization suffer from incomplete data

Check This Test for Free! Instantly.

Our free instant audit tool checks for 90 issues in 90 seconds.

Then gives you a prioritized list of items to tackle.

No cost, no sales call... just free goodness.
‍

Run a free instant audit
Google Analytics audit test results.

How to Conduct This Test

Basic Tests

  • In GA4 > Explore, build a Free-form report:
    • Dimensions: Session source/medium
    • Metrics: Sessions, Conversions, Revenue
    • Filter for Session source = (not set)
    • Add dimensions like Landing page, Device category, or Country to detect patterns

Advanced QA

  • In BigQuery, run the below query:
    SELECT session_source, session_medium, COUNT(*) AS sessions
    FROM `your_dataset.events_*`
    WHERE session_source IS NULL OR session_source = '(not set)'
    GROUP BY session_source, session_medium
    ORDER BY sessions DESC;
  • Seeing a meaningful volume of (not set) source traffic means you are losing critical attribution insights.

Automated, Free Audit

Want to automatically detect and categorize these sessions? Run our Instant Audit

Or hire a pro to help restore full source visibility.

How To Fix

  • Ensure all campaign and traffic links include utm_source, even if the rest of the UTM parameters are present
  • A missing utm_source will cause the entire session to be listed as (not set)
  • Use standardized UTM tagging templates across all marketing platforms, especially:
    • Email links
    • Paid social ads
    • Partner or affiliate links
  • Avoid using redirects that strip query parameters, especially from platforms like Facebook, LinkedIn, or email tools
  • Check for JavaScript errors or tag firing delays that might prevent GA4 from capturing source/medium
  • In tag manager setups, ensure that UTM parameters are preserved and passed to GA4 without modification
  • Hire a pro to audit your attribution setup and ensure every session has a source you can trust and act on.

Tips from a Google Analytics Consultant

Focus on Insights

Every Google Analytics audit should result in a plan for more insights.

‍

An insight is:

  • something you don't know
  • and can act on to improve performance

The Goal

Identify and remove insight blockers. Don't get tempted to track things you can't act on!

Hire a Google Analytics Consultant
Google Analytics consultant