What This Rule Detects

Identifies when utm_source and utm_medium combinations don't make logical sense, such as "google" with "social" medium or "facebook" with "organic" medium. These mismatches break GA4's automatic channel grouping, cause traffic misclassification, and create confusion in attribution reports.

Why It Matters

Business Impact:

• Channel misclassification - Google Ads traffic appears as "Social" instead of "Paid Search"
• Reporting confusion - Stakeholders see Facebook traffic in wrong channel
• Trend analysis broken - Cannot track channel performance accurately over time
• Budget decisions flawed - Optimize wrong channels based on misattributed data

Technical Impact:

• GA4 channel grouping uses BOTH utm_source and utm_medium
• Illogical combinations confuse automated classification
• Traffic may appear in "Unassigned" or wrong channel group
• Breaks channel-based attribution models and conversion paths

Real Example:

• Campaign URL: utm_source=google&utm_medium=social
• Logic error: Google is a search engine, not a social platform
• GA4 confusion: utm_source says "search engine", utm_medium says "social media"
• Channel classification: May appear as "Unassigned" or wrong channel
• Report impact: Google Ads spend shows up in "Social" channel, breaking paid search analysis
• Decision impact: You think social performs well (it's actually Google Ads), invest more in wrong channel

Common Scenarios

Scenario 1: Platform-Medium Mismatch

Using social medium for search platforms or vice versa:

Scenario 2: Email Platform with Wrong Medium

Email platforms tagged with non-email medium:

Scenario 3: Social Platform with Search Medium

Social platforms tagged as search traffic:

How to Fix

Step 1: Understand Correct Source-Medium Combinations

Logical pairing rules by platform type:

Search Platforms (Google, Bing, DuckDuckGo):

✅ utm_source=google + utm_medium=cpc (Google Ads paid search)
✅ utm_source=google + utm_medium=organic (SEO traffic - but don't tag this)
✅ utm_source=bing + utm_medium=cpc (Microsoft Ads)
❌ utm_source=google + utm_medium=social (illogical - Google isn't social)
❌ utm_source=bing + utm_medium=email (illogical - Bing isn't email)

Social Platforms (Facebook, Twitter, LinkedIn, Instagram):

✅ utm_source=facebook + utm_medium=social (organic posts)
✅ utm_source=facebook + utm_medium=cpc (Facebook Ads paid)
✅ utm_source=facebook + utm_medium=paidsocial (alternative for paid)
✅ utm_source=linkedin + utm_medium=social (organic)
❌ utm_source=facebook + utm_medium=organic (confusing - use 'social')
❌ utm_source=twitter + utm_medium=email (illogical)

Email Platforms (Mailchimp, SendGrid, Constant Contact):

✅ utm_source=mailchimp + utm_medium=email (correct)
✅ utm_source=newsletter + utm_medium=email (correct)
✅ utm_source=sendgrid + utm_medium=email (correct)
❌ utm_source=mailchimp + utm_medium=social (illogical)
❌ utm_source=newsletter + utm_medium=cpc (illogical)

Display Networks:

✅ utm_source=google-display + utm_medium=display
✅ utm_source=banner-network + utm_medium=display
❌ utm_source=display-network + utm_medium=social (illogical)

Partner/Referral Traffic:

✅ utm_source=partner-blog + utm_medium=referral
✅ utm_source=techcrunch + utm_medium=referral
❌ utm_source=partner-blog + utm_medium=cpc (unless paid partnership)

Step 2: Identify Conflicting Combinations in Your Data

Use UTMGuard audit results:

1. Review "Conflicting Source and Medium" flagged issues
2. Note which source-medium pairs are illogical
3. Identify affected campaigns and traffic volume

Manual GA4 analysis:

1. Reports → Acquisition → Traffic acquisition
2. Add dimensions: "Session source" and "Session medium"
3. Scan for illogical combinations:
   • Search engines with social medium
   • Social platforms with organic medium (should be 'social')
   • Email sources with non-email medium

Step 3: Fix Source-Medium Mismatches

Decision tree for corrections:

If utm_source is correct but utm_medium is wrong:

• Keep the source, change medium to match platform type
• Example: google + social → google + cpc

If utm_medium is correct but utm_source is wrong:

• Keep the medium, change source to match
• Example: google + email → mailchimp + email

If both are wrong:

• Determine actual traffic source
• Apply correct source + medium combination
• Example: facebook + organic → facebook + social

Step 4: Update Active Campaigns

Google Ads (search platform):

Incorrect combinations to fix:
❌ utm_source=google&utm_medium=social
❌ utm_source=google&utm_medium=email
❌ utm_source=google&utm_medium=referral

Correct:
✅ utm_source=google&utm_medium=cpc (paid search)
✅ utm_source=google&utm_medium=display (Google Display Network)

Facebook/Instagram Ads:

Incorrect combinations to fix:
❌ utm_source=facebook&utm_medium=organic (confusing)
❌ utm_source=facebook&utm_medium=search (illogical)
❌ utm_source=instagram&utm_medium=cpc (use 'social' or 'paidsocial')

Correct:
✅ utm_source=facebook&utm_medium=social (organic posts)
✅ utm_source=facebook&utm_medium=cpc (paid ads - acceptable)
✅ utm_source=facebook&utm_medium=paidsocial (paid ads - clearer)
✅ utm_source=instagram&utm_medium=social

Email Campaigns:

Incorrect combinations to fix:
❌ utm_source=mailchimp&utm_medium=social
❌ utm_source=mailchimp&utm_medium=referral
❌ utm_source=newsletter&utm_medium=cpc

Correct:
✅ utm_source=mailchimp&utm_medium=email
✅ utm_source=newsletter&utm_medium=email
✅ utm_source=sendgrid&utm_medium=email

Step 5: Document Correct Combinations for Your Team

Create reference guide:

# UTM Source-Medium Combinations Guide
 
## Rules
utm_source = WHO/WHERE (the platform)
utm_medium = HOW (the method/channel type)
These MUST be logically compatible!
 
## Correct Combinations by Platform
 
### Search Engines
- Google Ads: utm_source=google + utm_medium=cpc
- Bing Ads: utm_source=bing + utm_medium=cpc
- Never use: social, email, or referral medium with search sources
 
### Social Media Platforms
- Facebook organic: utm_source=facebook + utm_medium=social
- Facebook paid: utm_source=facebook + utm_medium=cpc OR paidsocial
- Twitter: utm_source=twitter + utm_medium=social
- LinkedIn: utm_source=linkedin + utm_medium=social
- Never use: organic or search medium (use 'social' instead)
 
### Email Marketing
- ANY email source: utm_medium=email (always)
- Examples: mailchimp/email, sendgrid/email, newsletter/email
- Never use: social, cpc, or display medium with email sources
 
### Display Advertising
- Display networks: utm_medium=display (always)
- Examples: google-display/display, banner-network/display
- Never use: social or email medium with display sources
 
### Referral/Partner Traffic
- Partner sites: utm_medium=referral
- Examples: partner-blog/referral, techcrunch/referral
- Never use: organic or cpc (unless it's paid partnership)
 
## Red Flags (Never Use)
❌ google + social
❌ facebook + organic (use 'social' instead)
❌ mailchimp + referral
❌ twitter + cpc (use 'social' or 'paidsocial')
❌ email-source + social

Examples

❌ Incorrect Examples

Google with social medium:
?utm_source=google&utm_medium=social&utm_campaign=ads
Problem: Google is a search engine, not a social platform
GA4 Impact: May classify as "Unassigned" or wrong channel
Fix: utm_source=google&utm_medium=cpc

Facebook with organic medium:
?utm_source=facebook&utm_medium=organic&utm_campaign=post
Problem: Confusing - "organic" implies search, Facebook is social
GA4 Impact: May not classify correctly in "Organic Social"
Fix: utm_source=facebook&utm_medium=social

Mailchimp with referral medium:
?utm_source=mailchimp&utm_medium=referral&utm_campaign=newsletter
Problem: Mailchimp is an email platform, not a referral source
GA4 Impact: Appears in "Referral" channel instead of "Email"
Fix: utm_source=mailchimp&utm_medium=email

LinkedIn with search medium:
?utm_source=linkedin&utm_medium=organic&utm_campaign=company-page
Problem: LinkedIn is social media, not a search engine
GA4 Impact: May classify as "Organic Search" instead of "Organic Social"
Fix: utm_source=linkedin&utm_medium=social

✅ Correct Examples

Google Ads (search):
?utm_source=google&utm_medium=cpc&utm_campaign=shoes-spring-2024
Result: Properly classified as "Paid Search"
GA4 Channel: Paid Search
Logic: Search engine + paid search medium = correct

Facebook organic post:
?utm_source=facebook&utm_medium=social&utm_campaign=product-launch
Result: Properly classified as "Organic Social"
GA4 Channel: Organic Social
Logic: Social platform + social medium = correct

Email campaign:
?utm_source=mailchimp&utm_medium=email&utm_campaign=weekly-digest
Result: Properly classified as "Email"
GA4 Channel: Email
Logic: Email platform + email medium = correct

Partner referral:
?utm_source=partner-techcrunch&utm_medium=referral&utm_campaign=product-review
Result: Properly classified as "Referral"
GA4 Channel: Referral
Logic: External site + referral medium = correct

GA4 Impact Analysis

Channel Grouping:

• Conflicting combinations → "Unassigned" or wrong channel
• Logical combinations → Proper channel classification
• Impact: Reporting accuracy and channel analysis

Default Channel Group Rules:

• GA4 uses BOTH source and medium for classification
• Mismatches confuse the channel grouping algorithm
• Example: google + social doesn't match any channel definition

Attribution Models:

• Conflicting pairs → Attribution may credit wrong channel
• Correct pairs → Accurate multi-touch attribution
• Impact: Campaign ROI calculations and budget decisions

Reporting Clarity:

• Conflicting pairs → Confusing reports (Google in Social channel)
• Correct pairs → Clear, intuitive reports
• Impact: Stakeholder trust in data and decision-making

Detection in UTMGuard

UTMGuard automatically detects conflicting source-medium combinations:

1. Analyzes utm_source and utm_medium pairs
2. Compares against logical platform-medium mappings
3. Flags illogical combinations (search + social, email + referral, etc.)
4. Counts affected sessions
5. Reports specific campaigns with conflicting pairs

Audit Report Shows:

• Total sessions with conflicting combinations
• Specific mismatches detected
• Suggested corrections (proper medium for the source)
• Priority ranking by traffic volume

Related Validation Rules

Frequently Asked Questions

Q: Can I use utm_medium=cpc for Facebook Ads?

A: Technically yes, and GA4 will classify it as "Paid Social". However, utm_medium=social or paidsocial is clearer for reporting. Both work, but consistency matters. Choose one and stick with it for all social ads.

Q: What's the difference between "organic" and "social" medium?

A: "organic" = organic search (Google, Bing SEO). "social" = social media platforms (Facebook, Twitter, LinkedIn). Use "social" for social platforms, even if unpaid. Don't tag organic search traffic at all (GA4 detects it automatically).

Q: Should I use utm_medium=referral for social media shares?

A: No. Use utm_medium=social for ALL social media traffic (paid and organic). "referral" is for external websites/blogs that link to you, not social platforms.

Q: What if traffic comes from Google but via Gmail (email)?

A: If someone clicks a link in a Gmail message, use utm_source=gmail&utm_medium=email (or your email platform if you sent it). Don't use utm_source=google for email traffic just because Gmail is Google-owned.

Q: Can utm_source=facebook have utm_medium=cpc?

A: Yes, this works and GA4 classifies it as "Paid Social". Some prefer utm_medium=paidsocial for clarity, but cpc is acceptable for paid social ads. Be consistent across all paid social campaigns.

Q: What about YouTube - is it social or video?

A: YouTube can use either utm_medium=social or utm_medium=video depending on your preference. Video is more specific. For YouTube ads, use utm_medium=video or utm_medium=cpc (both work). Be consistent.

Q: How do I fix historical data with conflicting combinations?

A: Historical data cannot be modified. For future analysis, create GA4 segments or custom channel groupings that reclassify the mismatched data based on source or medium alone.

Q: What if I'm truly unsure which medium to use?

A: Refer to the platform type: Search engines = cpc/organic, Social = social/paidsocial, Email = email, Partners = referral, Display = display. If still unsure, check GA4's Default Channel Group definitions for guidance.

External Resources

• GA4: Default Channel Group Definitions
• Google: Campaign URL Builder
• Best Practices for UTM Parameters
• GA4: Traffic Source Dimensions