Vocabulary · Volume 1 and Volume 2

Little's law

In a stable system, the average number of items present equals their arrival rate times the average time each spends there, $L = \lambda W$. It relates long-run averages, not percentiles or peaks.

The definition appears in the Volume 1 glossary and Volume 2 glossary. This page collects where the book uses the term and where the blog takes it up.