Five Whys vs Fishbone: When Each Wins

Two root cause techniques. The decision rule by incident type.

Five Whys

Linear causal chains. 'Service was down → DB was unreachable → connection pool exhausted → ...'

Best for: clear cause and effect; single failure mode.

Fishbone

Multiple contributing factors. People, process, technology, environment.

Best for: complex incidents with many contributing factors.

Limits

Five Whys stops at five. Some chains have more.

Fishbone is exploratory. Don't expect a single root cause.