Laws of Software Engineering

The Measurement cluster

How to measure without breaking the things you measure.

Why these together

A measurement programme that holds these together can survive scrutiny. One that misses any of them is for show. Goodhart says do not target. Gilb says measure even when hard. McNamara says do not ignore what is hard to measure. Vanity vs Actionable says measure things that change decisions. DORA is the proof that all of this can be done well. Leading and Lagging Indicators is the design discipline that makes it work.

• Law DORA / Accelerate Findings Four numbers predict whether a software organisation is performing well: how often you ship, how long changes take, how often changes break things, and how fast you recover when they do.
• Pattern Goodhart's Law Once a measurement becomes a target, it stops being a useful measurement.
• G Saying Gilb's Law Anything you need to measure can be measured in some way that is better than not measuring it at all.
• T Saying The McNamara Fallacy What can be measured easily gets attention. What cannot gets ignored. Eventually the unmeasured is declared unimportant.
• V Saying Vanity vs Actionable Metrics A vanity metric makes you feel good. An actionable metric changes a decision.
• L Principle Leading and Lagging Indicators Leading indicators predict future outcomes. Lagging indicators measure past outcomes. Use both, for different purposes.