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Learning and resources
Long-form explainers that build intuition, reference diagrams worth keeping open in another tab, and downloads. Courses are planned; the explainers here are the foundation they will build on.
Explainers and tutorials
How long does inventory need to last? Lead time, review period, and the horizon you choose
Every order has to last until the next order arrives, which is lead time plus review period. The review period is a decision with its own economics, its best value differs by SKU, and lengthening it is rarely the right way to buy availability. A companion to the guide on order economics.
ExplainerHow much to order: critical ratios, EOQ, and why weeks of cover is the wrong question
Two SKUs with the same forecast should not get the same order. A visual guide to the economics of stock: probabilistic forecasts, the critical ratio, economic order quantity, and why a planning horizon is not a number of weeks of cover.
ExplainerWhere should the next dollar of inventory go? Allocating a budget across SKUs
When the budget cannot cover every SKU's optimal buy, the usual answers are one service level for all or an equal cut. Both allocate by rule. Ranking every unit by its expected return per dollar allocates by value, and the difference grows as money gets tight.
Reference diagrams
The original Data Pattern Pro optimization references, at full resolution.
Optimization methods decision flowchart
Choose a method from your problem's structure, with implementing software for each branch.
Optimization classification hierarchy
How optimization problems are classified, with definitions and examples.
Is linear/integer programming suitable?
A four-question test for whether LP, IP, or MIP fits.
Memoization
Fibonacci with and without a cache, and the recursion tree that explains the speedup.
Downloads and books
Rethinking MILP as a Policy
Embedding MILP in sequential decision analytics. PDF, 30 pages.
The MILP Optimization Handbook
Formulation and practice for mixed-integer programming.
The Linearization Handbook for MILP Optimization
Modeling tricks that turn intractable formulations into ones a solver can handle.
The Decision Factory
A novel about decisions under uncertainty. Foreword by Warren B. Powell.
Courses
Structured courses on formulation, inventory economics, and sequential decisions.