On metrics

Some examples of wrong metrics

Code coverage

public void dummy_test_to_improve_coverage() {
Math.add(1, 1); // 1
// Oops, no assertion... // 2
  1. Math.add() will be executed
  2. But there’s no assertion on the result

Docker image size

Application startup time

Measuring influences the measured metric

Measuring is challenging

Measuring narrows down your perspective


  • Good metrics require an understanding of the context
  • The act of measuring itself will change the context, whether you like or not
  • The more relevant the metric, the harder it will be to measure correctly
  • Whatever the metric, it doesn’t reflect reality



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