A vacant slot in a downstream WIP limit signals permission to pull new work.
When a team groups multiple features into a single massive release, they introduce compounding risks. Large batches increase the time between the start of work and the extraction of value. They also delay testing, which makes bugs harder to isolate and resolve. The Benefits of Small Batches
Once you know the Cost of Delay, you can use to sequence your backlog.
To make small batches sustainable, organizations must lower the transaction costs of planning, testing, and releasing products. This is achieved through cadence and synchronization. A vacant slot in a downstream WIP limit
The manufacturing or operational cost per unit.
Development cost, product cost, schedule risk, and product performance.
: Push decision-making to the people with the most immediate knowledge to maintain high-speed flow under uncertainty. Get Your Copy They also delay testing, which makes bugs harder
Large batches of work (e.g., massive quarterly releases) introduce systemic risk. They require complex testing cycles, create massive merge conflicts, and delay customer validation.
by Donald G. Reinertsen is a seminal work that applies economic theory and queueing science to optimize product development cycles.
WSJF=Cost of DelayJob Size / DurationWSJF equals the fraction with numerator Cost of Delay and denominator Job Size / Duration end-fraction This is achieved through cadence and synchronization
Donald Reinertsen’s The Principles of Product Development Flow
The primary objective of product development is to maximize life-cycle profits. Reinertsen argues that most organizations fail to quantify the Cost of Delay (CoD)