Overview
Inventory Theory focuses on how much to order, when, and where to hold it. In the map of OR, it connects EOQ, (s, S) policies, Newsvendor to decisions that must be modeled, solved, explained, and revised as evidence changes.
EOQ, (s, S) policies, newsvendor, and multi-echelon inventory — balancing holding cost, ordering cost, and service level under demand uncertainty. The practical use case is clearest in adjacent OR applications, where the method helps turn constraints and tradeoffs into a decision artifact someone can inspect.
Core ideas
EOQ
EOQ is a core checkpoint for Inventory Theory: define it concretely, attach units or rules where possible, and test whether stakeholders interpret it the same way.
(s, S) policies
(s, S) policies is a core checkpoint for Inventory Theory: define it concretely, attach units or rules where possible, and test whether stakeholders interpret it the same way.
Newsvendor
Newsvendor is a core checkpoint for Inventory Theory: define it concretely, attach units or rules where possible, and test whether stakeholders interpret it the same way.
Multi-echelon
Multi-echelon is a core checkpoint for Inventory Theory: define it concretely, attach units or rules where possible, and test whether stakeholders interpret it the same way.
Safety stock
Safety stock is a core checkpoint for Inventory Theory: define it concretely, attach units or rules where possible, and test whether stakeholders interpret it the same way.
How to use it
- 1Start with a concrete case from the surrounding OR area: write the decision, time horizon, actors, and objective in operational language.
- 2Translate the problem into EOQ, (s, S) policies, and Newsvendor; define units and data sources for each one.
- 3Build a small instance of Inventory Theory that can be solved or simulated by hand inspection before using full production data.
- 4Compare the recommendation against a baseline policy, not just against mathematical optimality.
- 5Document assumptions, sensitivity results, and the conditions under which the recommendation should be revisited.
Applications
Use this topic as a building block in nearby OR models; connect it to a concrete decision before treating it as a standalone application area.
Common pitfalls
- Applying Inventory Theory because the label sounds appropriate while leaving the actual decision boundary vague.
- Treating EOQ as a technical detail instead of a modeling choice that affects the recommendation.
- Reporting one answer without showing sensitivity to demand, capacity, costs, or behavioral assumptions.
- Ignoring implementation details such as data quality, explainability, ownership, and how users will override bad recommendations.
Resources
- Foundations of Inventory Management — Zipkin
Topic-specific source curated for Inventory Theory.
- MIT OCW 6.231 — Dynamic Programming and Stochastic Control
Dynamic programming and stochastic control lectures for sequential decision models.
- MIT OCW 6.262 — Discrete Stochastic Processes
Poisson processes, Markov chains, renewal processes, and stochastic-process foundations.
- INFORMS — FAQs About O.R. & Analytics
Use this for the professional definition of OR, analytics, decision support, and applied practice.