Affected Events %: Share of Events with Quality Issues

The share of your total events impacted by a specific diagnostic issue.

Formula

Affected Events % = Affected Event Count ÷ Total Events × 100

Formula Components

Metric	Definition
Affected Event Count	Number of events impacted by this diagnostic issue
Total Events	Total number of events sent during the period

Metadata
Type	Percentage
Data Source	Meta Ads
Aggregation	Average

Example

Your pixel has 3 active diagnostics. Here’s how they affect your events:

Diagnostic Issue	Affected %	Priority
Missing email hash	42.3%	High
Invalid phone format	8.7%	Medium
Missing external_id	2.1%	Low

The “Missing email hash” issue impacts 42.3% of your events and should be fixed first.

How It Works

Meta analyzes your event data and flags quality issues that reduce matching accuracy. Affected Events % shows what portion of your total event volume is impacted by each specific issue. Higher percentages indicate issues affecting more of your data.

When to Use

Scenario	Action
Prioritizing fixes	Address issues with the highest affected % first
Measuring fix impact	Compare before/after to confirm resolution
Tracking data quality	Monitor trends over time for quality regressions
Resource allocation	Focus engineering time on highest-impact issues

Metric	Relationship
Affected Event Count	Absolute count of events (this metric shows the percentage)
Diagnostics Count	Total number of active diagnostic issues
EMQ Score	Overall quality score impacted by these issues

See all EMQ metrics →

Match Key Potential ACR Affected Event Count

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​Formula

​Formula Components

​Example

​How It Works

​When to Use

​Related Metrics

Formula

Formula Components

Example

How It Works

When to Use

Related Metrics