Metrics Reference

Technical reference for metrics in Confidence Metrics.

This section provides technical specifications and reference information for metrics.

For conceptual explanations of metrics, see Metrics in the Metrics Concepts page.

Metric Types

Average Metrics

Aggregate a single measurement across entities:

{
  "typeSpec": {
    "averageMetricSpec": {
      "measurement": {
        "name": "purchase_amount",
        "repeated": false
      },
      "aggregation": {
        "type": "AGGREGATION_TYPE_SUM"
      }
    }
  }
}

Ratio Metrics

Compute a ratio of two aggregated measurements:

{
  "typeSpec": {
    "ratioMetricSpec": {
      "numerator": {
        "measurement": {
          "name": "converted",
          "repeated": false
        },
        "aggregation": {
          "type": "AGGREGATION_TYPE_SUM"
        }
      },
      "denominator": {
        "measurement": {
          "name": "eligible",
          "repeated": false
        },
        "aggregation": {
          "type": "AGGREGATION_TYPE_SUM"
        }
      }
    }
  }
}

Aggregation Types

Type	Description	Use Case
AGGREGATION_TYPE_SUM	Sum all values	Total revenue, total conversions
AGGREGATION_TYPE_COUNT	Count all occurrences	Number of events, session count
AGGREGATION_TYPE_COUNT_DISTINCT	Count unique values	Unique items viewed, distinct categories
AGGREGATION_TYPE_MAX	Maximum value	Highest price, longest session
AGGREGATION_TYPE_MIN	Minimum value	Lowest price, shortest session
AGGREGATION_TYPE_UNIQUE	Single unique value (fails if multiple)	Latest status, final state

Time Windows

Aggregation Window

Duration after exposure to aggregate measurements:

"aggregationWindow": "604800s"  // 7 days in seconds

Common windows:

• 86400s: 1 day
• 604800s: 7 days (1 week)
• 1209600s: 14 days (2 weeks)
• 2592000s: 30 days (~1 month)

Exposure Offset

Delay before starting measurement:

"exposureOffset": "0s"  // Start immediately

Use cases:

• 0s: Immediate effect (UI changes, performance)
• 86400s: 1-day delay (email campaigns)
• 604800s: 1-week delay (long-term behavior)

Variance Reduction (CUPED)

Variance reduction improves statistical power by reducing noise in metric estimates:

Enabled (Default)

{
  "varianceReductionConfig": {
    "disabled": false
  }
}

Recommended for most metrics. Requires pre-exposure data.

Disabled

{
  "varianceReductionConfig": {
    "disabled": true
  }
}

Use when:

• No pre-exposure data available
• Metric is new user only
• Testing CUPED impact

Metric Resource Name Format

Reference metrics using the resource name format:

metrics/{metric_id}

Example: metrics/conversion-rate, metrics/average-revenue

Required Fields

Field	Type	Description
displayName	string	Human-readable metric name
entity	string	Entity resource name (for example, entities/user)
factTable	string	Fact table resource name
aggregationWindow	string	Duration in seconds (ISO 8601)
exposureOffset	string	Duration in seconds (ISO 8601)
typeSpec	object	Average or ratio metric specification

Best Practices

Choose Metric Types

• Average metrics: Use for continuous values (revenue, duration, ratings)
• Ratio metrics: Use for rates and percentages (conversion rate, CTR, success rate)

Aggregation Selection

• SUM: Default for most measurements (revenue, clicks, conversions)
• COUNT: When you only care about occurrence, not value
• COUNT_DISTINCT: When each unique value matters (unique products, categories)
• MAX/MIN: When extremes are important (peak load, worst performance)

Time Window Considerations

• Shorter windows (1-7 days): Faster results, earlier decisions
• Longer windows (14-30 days): Capture long-term effects, slower to significance
• Match business cycle: Align with purchase cycles, subscription periods

Variance Reduction

• Enable CUPED for most metrics to improve sensitivity
• Disable for new user metrics or when no historical data exists
• Monitor CUPED effectiveness in analysis results