Armstrong Metric

(noun) /ˈɑːmstrɒŋ ˈmɛtrɪk/

A metric which is too noisy to be monitored (does not indicate system health), but which nonetheless is helpful in understanding system behavior.

Named for Jeff Armstrong.

Example:

We can’t set up an alert for transient errors because the number/rate of transient errors is an Armstrong metric - it fluctuates outside of our control and sometimes for desired reasons.

These should be traced and sampled instead.