Little's law sets your lead time, not your roadmap

One piece of mathematics explains more delivery diagnostics than any framework we own: Little's law, which says that in a stable system, average items in progress equal arrival rate times average time in system. Rearranged for our purposes: time in system equals work in progress divided by throughput.

Read it as a manager. If your team completes ten changes a week and holds thirty in flight, the average change spends three weeks in flight, and no ceremony, standup or motivational quarter can make it otherwise while those two numbers hold. The only levers that shorten the wait are finishing faster or starting less, and of the two, starting less is available immediately, costs nothing, and is the one organizations resist hardest, because starting feels like progress and queueing is invisible.

This is why WIP limits, the least glamorous practice in the delivery canon, keep working wherever they are actually enforced. They are not a methodology preference. They are the law, obeyed on purpose instead of by accident. Count your in-flight work today, divide by last month's weekly completions, and you have your real lead time, whatever the roadmap says. The math was always running.