手法を比較

	Little's Law	バリューストリームマッピング（VSM）
分野	オペレーションズ・リサーチ	品質管理
系統	Regression model	Process / pipeline
提唱年	1961	1999
提唱者	John D. C. Little	Mike Rother & John Shook
種類	Exact queueing identity	Visual process analysis tool
原典	Little, J. D. C. (1961). A proof for the queuing formula: L = λW. Operations Research, 9(3), 383–387.	Rother, M., & Shook, J. (1999). Learning to See: Value Stream Mapping to Add Value and Eliminate Muda. Lean Enterprise Institute. ISBN: 978-0-9667843-0-5
別名	L = λW Theorem, Little's Theorem, Little's Result, Little Yasası	VSM, Material and Information Flow Mapping, Lean Flow Mapping, Değer Akış Haritalama
関連	3	3
概要	Little's Law is a fundamental theorem in queueing theory that relates the long-run average number of items in a stable system (L) to the long-run average arrival rate (λ) and the long-run average time an item spends in the system (W), expressed as L = λW. Introduced and rigorously proved by John D. C. Little in 1961, the law holds for virtually any stable stochastic system, requiring no assumptions about arrival distributions, service distributions, or queue disciplines.	Value Stream Mapping (VSM) is a lean management technique used to visualize, analyze, and improve the flow of materials and information required to bring a product or service from raw input to customer delivery. Introduced by Mike Rother and John Shook in their 1999 workbook Learning to See, VSM draws on the Toyota Production System tradition to expose waste, delays, and non-value-adding activities across the entire production value stream.