GA4 Reporting is Case-Sensitive: How It Affects Your Data

"Why do I have three rows for Facebook?"

You're looking at GA4's Traffic Acquisition report:

• facebook: 12,400 sessions
• Facebook: 8,900 sessions
• FACEBOOK: 3,200 sessions

Same platform. Three rows. Because GA4 is case-sensitive.

This isn't a bug. It's how GA4 processes data—and understanding it is critical to maintaining clean analytics.

How GA4 Processes Case

GA4 stores UTM parameters exactly as received.

If your URL says utm_source=Facebook, GA4 stores "Facebook" (capital F). If another URL says utm_source=facebook, GA4 stores "facebook" (lowercase f).

When reporting:

• "Facebook" and "facebook" are treated as two distinct values
• Each gets its own row
• Sessions are NOT automatically combined

Why? Database systems (like GA4's BigQuery backend) are case-sensitive by default for string comparisons.

Impact on Different Report Types

Traffic Acquisition Reports

Affected dimensions:

• Session source
• Session medium
• Session campaign
• First user source
• First user medium

Example fragmentation:

Total rows: 3 × 3 × 3 = 27 combinations for ONE campaign

Exploration Reports

Same issue in custom explorations:

• Free form reports
• Funnel analysis
• Path analysis
• Segment overlap

All treat case-sensitive values as distinct.

Conversion Reports

Attribution affected:

• First touch: May credit wrong case variation
• Last touch: May credit wrong case variation
• Data-driven: Model fragments across case variations

utm_medium vs Other Parameters

Critical: utm_medium (affects channel grouping)

Impact: Uppercase breaks channel assignment

utm_medium=cpc  → Paid Search ✅
utm_medium=CPC  → Unassigned ❌

Result: Traffic invisible in channel reports

Annoying: utm_source, utm_campaign, etc.

Impact: Data fragmentation only

utm_source=google  → Row 1 ✅
utm_source=Google  → Row 2 (separate row)

Result: Traffic visible, but split across multiple rows

Priority:

1. Fix utm_medium first (critical—breaks attribution)
2. Fix utm_source/campaign next (important—fragments data)
3. Fix utm_content/term last (nice to have—cleaner reporting)

Real Example: 47% Data Fragmentation

Company: SaaS with 50,000 monthly sessions

Export showed:

• 89 unique utm_source values
• 127 unique utm_campaign values

Investigation revealed:

• Actual sources: 23 platforms
• Actual campaigns: 31 campaigns
• Fragmentation: 47% of rows were duplicates due to case variations

Examples found:

Impact:

• Leadership thought we ran 127 campaigns (actually 31)
• Couldn't quickly identify top sources
• Pivot tables unreadable (too many rows)

After lowercase standardization:

• 89 sources → 23 sources (74% reduction)
• 127 campaigns → 31 campaigns (76% reduction)
• Reports instantly usable

How to Work with Case-Sensitive Data

Short-term: Manual Consolidation

Google Sheets:

1. Export GA4 data
2. Add "Clean" column: =LOWER(A2)
3. Pivot on clean column
4. See consolidated totals

Medium-term: Looker Studio Calculated Fields

Create reusable fields:

Clean Source: LOWER(Session source)
Clean Campaign: LOWER(Session campaign)
Clean Medium: LOWER(Session medium)

Use in all charts/tables instead of raw dimensions.

Long-term: Fix at Source

Standardize all UTM parameters to lowercase:

• Update URL builders
• Fix campaign templates
• Enforce with validation
• Quarterly audits

Prevention Strategies

1. Enforce Lowercase in URL Builder

Google Sheets formula:

=LOWER(TRIM(A2))  // Lowercase + remove extra spaces

2. Pre-Launch Validation

Before campaign launch:

• All UTM parameters lowercase
• No spaces or special characters
• Test URL in GA4 Realtime
• Verify single row created (not duplicates)

3. Team Training

One-page guide:

GA4 IS CASE-SENSITIVE

✅ DO:
- Use lowercase for all UTM parameters
- utm_source=facebook (lowercase)
- utm_campaign=spring_sale (lowercase)

❌ DON'T:
- utm_source=Facebook (title case)
- utm_campaign=Spring_Sale (mixed case)
- utm_source=FACEBOOK (all caps)

Remember: "facebook" ≠ "Facebook" ≠ "FACEBOOK"
Each creates a separate row in GA4.

FAQ

Can GA4 auto-consolidate case variations?

No. GA4 stores and reports data exactly as received. There's no built-in case normalization. You must consolidate manually in exports or use calculated fields in Looker Studio.

Why doesn't GA4 just ignore case?

Technical reasons:

• BigQuery (GA4's backend) is case-sensitive by default
• Changing would require processing overhead
• Could cause unintended side effects

Standardization reasons:

• Google wants consistent UTM practices across properties
• Forces marketers to follow conventions
• Documented standards (lowercase) have existed for years

Does this affect BigQuery exports?

Yes. If you export GA4 data to BigQuery, case sensitivity persists:

-- These return different results:
WHERE utm_source = 'google'    -- Matches only lowercase
WHERE utm_source = 'Google'    -- Matches only title case
WHERE LOWER(utm_source) = 'google'  -- Matches all variations

Always use LOWER() function for case-insensitive queries.

Can I create custom dimensions that auto-lowercase?

Not directly in GA4, but yes in Looker Studio:

1. Create calculated field
2. Formula: LOWER(Session source)
3. Use this dimension in all reports
4. Auto-consolidates regardless of source case

What about non-English characters (é, ñ, ü)?

GA4 supports UTF-8:

• Non-English characters work fine
• Still case-sensitive: café ≠ Café
• Best practice: Use English alphanumeric + underscores only
• Avoid accents/special characters for consistency

Will this ever change?

Unlikely. Case sensitivity is fundamental to how databases work. Google would need to:

• Rebuild GA4's data processing
• Risk breaking existing implementations
• Process billions of events differently

More likely: Google continues documenting lowercase standards and expects marketers to follow them.