So sánh phương pháp

	Định luật Little (L = λW)	Six Sigma DMAIC	Value Stream Mapping (VSM)
Lĩnh vực	Vận trù học	Quản lý chất lượng	Quản lý chất lượng
Họ	Regression model	Process / pipeline	Process / pipeline
Năm ra đời	1961	2014	1999
Người khởi xướng	John D. C. Little	Motorola; Pyzdek & Keller	Mike Rother & John Shook
Loại	Exact queueing identity	Structured process improvement methodology	Visual process analysis tool
Công trình gốc	Little, J. D. C. (1961). A proof for the queuing formula: L = λW. Operations Research, 9(3), 383–387.	Pyzdek, T., & Keller, P. (2014). The Six Sigma Handbook (4th ed.). McGraw-Hill. ISBN: 978-0-07-184053-9	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
Tên gọi khác	L = λW Theorem, Little's Theorem, Little's Result, Little Yasası	DMAIC Framework, Six Sigma Process Improvement Cycle, Define-Measure-Analyze-Improve-Control, Altı Sigma DMAIC	VSM, Material and Information Flow Mapping, Lean Flow Mapping, Değer Akış Haritalama
Liên quan	3	3	3
Tóm tắt	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.	Six Sigma DMAIC is a data-driven, five-phase process improvement methodology — Define, Measure, Analyze, Improve, and Control — used to reduce defects and process variation to fewer than 3.4 defects per million opportunities. Originating at Motorola in the 1980s and systematized by practitioners including Pyzdek and Keller, it is widely adopted in manufacturing, healthcare, finance, and service industries seeking sustained quality gains.	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.