Conflicting UTM Source-Medium Pairs That Break GA4 Attribution

Tom Richardson launched his LinkedIn ad campaign feeling confident. The UTM parameters looked perfect:

utm_source=linkedin
utm_medium=social
utm_campaign=product_launch

"LinkedIn is social media," he thought. "This makes total sense."

Two weeks later, his GA4 Channel report showed the campaign under "Unassigned"—not Paid Social. $18,000 in ad spend completely misattributed because GA4 couldn't reconcile "linkedin + social" for a paid campaign.

His CFO thought the campaign failed. Tom almost lost his job. All because of conflicting source-medium pairs.

What Are Conflicting Source-Medium Pairs?

Conflicting pairs = Source and medium combinations that contradict each other or violate GA4's channel grouping logic.

How GA4 Channel Grouping Works

GA4 uses source-medium combinations to assign traffic to channels:

The conflict: When source suggests one channel but medium suggests another, GA4 assigns to "Unassigned" or misclassifies entirely.

Common Conflicting Pairs

Why This Breaks Attribution

Example 1: LinkedIn Paid Social Disaster

Campaign setup:

utm_source=linkedin
utm_medium=social
utm_campaign=demand_gen_q4

What the marketer thought:

• "LinkedIn is a social platform, so medium=social makes sense"

What GA4 thinks:

• linkedin + social = Organic Social
• But wait, this is a paid campaign...
• GA4 assigns to "Unassigned" or misclassifies as Organic Social

The correct setup:

utm_source=linkedin
utm_medium=cpc
utm_campaign=demand_gen_q4

OR

utm_source=linkedin
utm_medium=paid-social
utm_campaign=demand_gen_q4

Impact:

Business consequence:

• CFO reviews Paid Social performance
• Doesn't see LinkedIn results
• Thinks Paid Social failed
• Cuts budget for successful channel

Example 2: Google Social Medium Error

Campaign setup:

utm_source=google
utm_medium=social
utm_campaign=youtube_awareness

The conflict:

• Source says "google" (search engine)
• Medium says "social" (social media)
• GA4 doesn't know which to trust

GA4's decision: Assigns to "Unassigned" or creates custom channel

Why it happened:

• Marketer thought YouTube = social platform
• Used medium=social
• But source=google conflicts with this

The correct setup:

utm_source=google-youtube
utm_medium=cpc
utm_campaign=youtube_awareness

Example 3: Facebook Email Medium

Campaign setup:

utm_source=facebook
utm_medium=email
utm_campaign=share_prompt

The conflict:

• Facebook is a social platform
• Email is an email channel
• These are mutually exclusive

Why it happened:

• Campaign involved Facebook users sharing content via email
• Marketer wanted to track the email sharing component
• Created nonsensical combination

The correct setup:

For Facebook organic sharing:

utm_source=facebook
utm_medium=social
utm_campaign=share_prompt

For actual email from Facebook:

utm_source=facebook-notification
utm_medium=email
utm_campaign=notification_click

Complete List of Conflicting Pairs

Paid Advertising Conflicts

Organic Social Conflicts

Email Conflicts

Search Engine Conflicts

How to Avoid Conflicting Pairs

Rule 1: Match Source Type to Medium Type

Source = Platform, Medium = Traffic Type

Social platforms:

• Organic: utm_source=facebook&utm_medium=social
• Paid: utm_source=facebook&utm_medium=cpc

Search engines:

• Organic: utm_source=google&utm_medium=organic
• Paid: utm_source=google&utm_medium=cpc

Email platforms:

• Always: utm_source=mailchimp&utm_medium=email

Display ads:

• Always: utm_source=platform&utm_medium=display

Rule 2: Use GA4's Standard Medium Values

GA4 recognizes these mediums:

✅ Recommended mediums:

• cpc - Paid advertising (Cost Per Click)
• ppc - Paid advertising (Pay Per Click)
• paid - General paid advertising
• organic - Organic search traffic
• social - Organic social media
• email - Email marketing
• referral - Referral traffic
• display - Display advertising
• banner - Banner ads
• affiliate - Affiliate links

❌ Avoid mixing these:

• Don't use organic with social sources
• Don't use social with search sources
• Don't use email with social sources
• Don't use cpc with email sources

Rule 3: Validate Before Launch

Pre-launch checklist:

Source-Medium Validation:
 
1. Does this source-medium pair make logical sense?
   - Can this platform (source) send this type of traffic (medium)?
 
2. Does this match GA4's channel grouping logic?
   - Will GA4 recognize this as the intended channel?
 
3. Is this medium appropriate for paid vs organic?
   - Paid campaigns: cpc, ppc, paid-social, display
   - Organic campaigns: social, organic, referral
 
4. Have I used this exact pair before consistently?
   - Check historical data for similar campaigns

Correct Source-Medium Combinations

Social Media Platforms

Facebook:

Organic posts: utm_source=facebook&utm_medium=social
Paid ads: utm_source=facebook&utm_medium=cpc
           OR utm_source=facebook-ads&utm_medium=cpc

LinkedIn:

Organic posts: utm_source=linkedin&utm_medium=social
Sponsored content: utm_source=linkedin&utm_medium=cpc
                    OR utm_source=linkedin-ads&utm_medium=cpc

Twitter:

Organic tweets: utm_source=twitter&utm_medium=social
Promoted tweets: utm_source=twitter&utm_medium=cpc

Instagram:

Organic posts: utm_source=instagram&utm_medium=social
Paid ads: utm_source=instagram&utm_medium=cpc

Search Engines

Google:

Organic search: utm_source=google&utm_medium=organic (auto-assigned by GA4)
Google Search Ads: utm_source=google&utm_medium=cpc (auto-tagged)
Google Display Ads: utm_source=google&utm_medium=display
                     OR utm_source=google-display&utm_medium=cpc
Google Shopping: utm_source=google&utm_medium=cpc (auto-tagged)

Bing:

Organic search: utm_source=bing&utm_medium=organic
Microsoft Ads: utm_source=bing&utm_medium=cpc

Email Platforms

Always use medium=email:

Mailchimp: utm_source=mailchimp&utm_medium=email
SendGrid: utm_source=sendgrid&utm_medium=email
Klaviyo: utm_source=klaviyo&utm_medium=email
HubSpot: utm_source=hubspot&utm_medium=email

Display & Banner Ads

Google Display: utm_source=google-display&utm_medium=display
Taboola: utm_source=taboola&utm_medium=display
Outbrain: utm_source=outbrain&utm_medium=display

Affiliate & Partner

Affiliate network: utm_source=cj-affiliate&utm_medium=affiliate
Partner referral: utm_source=partner-techcrunch&utm_medium=referral

How to Fix Existing Conflicting Pairs

Step 1: Identify Conflicts in GA4

Check for Unassigned channel traffic:

1. GA4 → Reports → Acquisition → Traffic Acquisition
2. Filter by: Default channel group = "Unassigned"
3. Export data with source and medium
4. Review each pair for conflicts

Step 2: Find Active Campaigns with Conflicts

Audit your active campaigns:

Platform: LinkedIn Ads
Current URLs: utm_source=linkedin&utm_medium=social
Issue: Paid campaign using organic medium
Fix: Change to utm_medium=cpc

Step 3: Update Campaign UTMs

For each platform:

LinkedIn Ads:

• Old: utm_source=linkedin&utm_medium=social
• New: utm_source=linkedin&utm_medium=cpc
• Update in Campaign Manager → Ads → URL parameters

Facebook Ads:

• Old: utm_source=facebook&utm_medium=organic
• New: utm_source=facebook&utm_medium=cpc
• Update in Ads Manager → Ad creative → URL parameters

Step 4: Document Correct Pairs

Create a source-medium pairing guide:

# Approved Source-Medium Combinations
 
| Platform | Campaign Type | Source | Medium |
|----------|---------------|--------|--------|
| Facebook | Organic | facebook | social |
| Facebook | Paid | facebook-ads | cpc |
| LinkedIn | Organic | linkedin | social |
| LinkedIn | Paid | linkedin-ads | cpc |
| Google | Organic Search | google | organic |
| Google | Paid Search | google | cpc |
| Mailchimp | Email | mailchimp | email |
 
## NEVER USE:
❌ google + social
❌ linkedin + email
❌ facebook + organic (use 'social' for organic)
❌ mailchimp + cpc

FAQ

Can I use custom medium values?

Yes, but be cautious. GA4 assigns custom mediums to "Unassigned" channel unless you create custom channel groupings.

Recommended: Stick to standard mediums (cpc, social, email, organic, referral, display) for automatic channel assignment.

What if I want to differentiate paid social from paid search?

Option 1: Use different sources

Google Ads: utm_source=google-search&utm_medium=cpc
Facebook Ads: utm_source=facebook-ads&utm_medium=cpc

Option 2: Use custom mediums

Paid Search: utm_medium=cpc
Paid Social: utm_medium=paid-social

Both work. Option 1 is simpler.

Is "utm_medium=social" wrong for paid social ads?

It's unclear. Best practice:

• Organic social: utm_medium=social
• Paid social: utm_medium=cpc or utm_medium=paid-social

This clearly differentiates paid vs organic.

What about YouTube ads—is it social or video?

YouTube is complex:

GA4's default: Google YouTube ads = Paid Video channel

Recommended:

utm_source=google-youtube&utm_medium=cpc

Avoid:

utm_source=youtube&utm_medium=social (conflicting)

Can I use both "cpc" and "ppc" for paid ads?

Pick one and be consistent.

• cpc = Cost Per Click (more common)
• ppc = Pay Per Click (older convention)

Recommendation: Use cpc for consistency with Google Ads auto-tagging.

What if my agency uses conflicting pairs?

Require them to fix it. Provide your approved source-medium pairing guide and make compliance mandatory.

Email template:

Subject: Required Update to Campaign UTM Parameters

Our GA4 data shows campaigns are being assigned to "Unassigned" channel
due to conflicting source-medium pairs.

Required changes:
- LinkedIn Ads: Change utm_medium from "social" to "cpc"
- Facebook Ads: Change utm_medium from "organic" to "cpc"

See attached source-medium pairing guide for all platforms.

Please update all active campaigns by [date].

Related: Conflicting Channel Medium Attribution Rule