Change Failure Rate

Change Failure Rate: Percentage of deployments that cause incidents.

Formula

Change Failure Rate = Deployments causing incidents / Total deployments × 100

Computable definition

The canonical formula in the GASP formula grammar. The MCP server compiles it to SQL over the datasets listed below.

count_distinct(field.deployment_id where field.incident_id is not null) / count_distinct(field.deployment_id)

Unit: percent (the formula yields an unscaled ratio)

Data requirements

Grain: Per event · Frequency: Per deploy · Aggregation: event · Staged: no · Main source: CI/CD.

Field	Dataset	Type
`deploy_date`	deployment	timestamp
`deployment_id`	deployment	string
`incident_id`	deployment	string

Example SQL (Postgres)

SELECT (CAST((SELECT COUNT(DISTINCT deployment_id) FROM deployment WHERE deploy_date >= :period_start AND deploy_date < (:period_end + INTERVAL '1 day') AND incident_id IS NOT NULL) AS DOUBLE PRECISION) / NULLIF((SELECT COUNT(DISTINCT deployment_id) FROM deployment WHERE deploy_date >= :period_start AND deploy_date < (:period_end + INTERVAL '1 day')), 0)) AS change_failure_rate

From an agent: with the GASP MCP server, call lookup_metric({ "name": "Change Failure Rate" }) or generate_query({ "metric": "Change Failure Rate", "adapter": "<your adapter JSON>" }).

Benchmarks

Elite: 0-15%
High: 16-30%
Medium: 31-45%
Low: 46-60%

What It Tells You

Deployment quality and release process health.

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