Little's law
In a stable system, the average number of items inside equals the average rate at which they pass through multiplied by the average time each one spends inside. Proved by John Little in 1961.
In plain English
It needs almost no assumptions: tasks can be big or small, regular or random, and over a long enough stretch the identity still holds. Rearranged, it says the average time to finish is the work in progress divided by the number finished per period. So with the same pace, less started work means less waiting, which is why teams cap work in progress.
Uncle Gary explains
A team that finishes 10 requests a week with 50 in progress takes 5 weeks per request on average; with 25 in progress, 2.5 weeks.
Why it matters for your money
The same rule applies to a pile of half-read research or a list of positions to review: the more you keep open, the longer each one waits for your attention.
Where we tested it
Related terms
All glossary terms. Educational content, not financial advice.