The Engine Room
Operations management runs the transformation at the heart of every firm: inputs to outputs. Its craft is balancing quality, speed, dependability, flexibility, and cost—five forces that pull against each other.
Process types trade volume against variety. Moving right buys unit cost but loses flexibility; choosing a process type is choosing a strategy.
| Type | Example | Volume | Variety |
|---|---|---|---|
| Project | A dam | One | Total |
| Job shop | Custom furniture | Low | High |
| Batch | Bakery runs | Medium | Medium |
| Line | Car assembly | High | Low |
| Continuous | Refinery | Massive | None |
Capacity sets the ceiling. Utilization = actual output / design capacity. Running near 100% looks efficient but behaves badly: queues explode nonlinearly as utilization approaches capacity, which is why emergency rooms and highways jam at 95% efficiency.
Inventory and Lean
Inventory buffers supply rhythm against demand rhythm. Ordering often brings setup fees; ordering rarely brings holding fees. The Economic Order Quantity (EOQ) minimizes their sum:
Where is annual demand, is cost per order, and is holding cost per unit-year. The cost curve is flat near the optimum, so being roughly right is cheap.
Lean (Toyota) wages war on waste: overproduction, waiting, transport, over-processing, inventory, motion, and defects. Its tools include just-in-time flow, kanban signals, and kaizen (continuous improvement).
Pitfall: Inventory removed is also buffer removed. Efficiency and fragility are always bought together.