Goodhart's Law

When a measure becomes a target, it ceases to be a good measure.

-- Charles Goodhart, 1975

Originating in economics, this law posits a pessimistic view of measuring the success of software. Once a given measure, for example lines of code, becomes reified as the measure of success, then software developers can readily maximize that measure, for example by adding a lot of superfluous comments or other unnecessary code. This law joins others which indicate the difficulty of measuring software projects, such as Hofstadter’s.