Operations Management

The Engine Room

Operations management runs the transformation at the heart of every firm: inputs → process → outputs. Its craft is designing that transformation to deliver quality, speed, dependability, flexibility, and cost — knowing the five pull against each other.

Process types trade volume against variety: project (one dam), job shop (custom furniture), batch (bakery runs), line (car assembly), continuous (refinery). Moving right buys unit cost and loses flexibility — choosing a process type is choosing a strategy.

Capacity decisions set the ceiling: utilization = actual output / design capacity. Running near 100% looks efficient and behaves badly — queues explode nonlinearly as utilization approaches capacity, which is why the emergency room and the highway both jam at '95% efficient.'

Inventory buffers the mismatch between supply rhythm and demand rhythm. Its central trade-off: ordering often costs setup fees; ordering rarely costs holding fees. The Economic Order Quantity minimizes their sum:

$$EOQ = \sqrt{\frac{2DS}{H}}$$

with $D$ annual demand, $S$ cost per order, $H$ holding cost per unit-year. Total cost is a U: order-frequency costs fall with quantity while holding costs rise linearly, and the EOQ sits at the bottom — famously flat near the optimum, so being roughly right is cheap.

Quality evolved from inspection (catch defects) through statistical process control (watch the process) to Total Quality Management and Six Sigma (build quality in, everyone's job). The economics: prevention is the cheapest defect you ever fix.

Lean (Toyota) reframes everything as war on waste — the seven classics: overproduction, waiting, transport, over-processing, inventory, motion, defects. Its instruments: just-in-time flow (produce what's pulled, when pulled), kanban signals, and kaizen — continuous small improvements by the people doing the work. Lean's fine print, rediscovered every supply-chain crisis: inventory removed is also buffer removed; efficiency and fragility are bought together.

Process types: volume vs variety

Tip: Utilization is nonlinear: queues explode as you approach 100% of capacity. The plant that schedules to 85% is not leaving money on the table — it is buying the slack that keeps promises deliverable.