Revise Production planning for IB Business Management (5.6)

Every finished product is the end of a supply chain — the network of suppliers, producers, distributors and retailers that turns raw materials into something a customer buys. Operations planning is how a business coordinates its part of that chain: it forecasts demand, then organises materials, labour, machinery and capacity so the firm can meet that demand efficiently and on time. Three planning tools carry most of the weight and make up the rest of this lesson: capacity utilisation (are we using our resources well?), stock control (do we have the right materials at the right time?), and the make-or-buy decision (should we produce a part or buy it in?). Get these right and the firm stays efficient, liquid and responsive; get them wrong and it either runs dry mid-production or drowns in idle stock and unused capacity.

Capacity utilisation measures how much of a firm's maximum possible output is actually being produced. It matters because fixed costs (rent, machinery, salaried staff) are the same whether the factory runs flat out or half empty — so the more you produce, the more units share those fixed costs, and the lower the average cost per unit. A high utilisation rate therefore usually means lower unit costs and assets working hard. But a rate pushed too close to 100% removes all slack: there is no time for maintenance, no room for rush orders and no margin for error, which strains machinery and staff and can raise defects. A rate that is too low leaves fixed costs spread over too few units, raising average cost. Most firms aim for roughly 85–95%, but the right level depends on how predictable demand is.

$\text{Capacity utilisation (\%)} = \frac{\text{Actual output}}{\text{Maximum possible output}} \times 100$

Holding stock is a balancing act. Too much stock ties up working capital and adds holding costs — storage, insurance, security and the risk of goods becoming obsolete, perishing or being damaged. Too little stock risks stockouts that halt production, lose sales to competitors and force expensive emergency orders. The stock-control chart is the tool that keeps inventory in the safe zone between those extremes. Read from bottom to top it shows the buffer (minimum) stock, the reorder level that triggers a new order, the reorder quantity that is delivered, the lead time between order and delivery, and the maximum stock the firm will hold. Reading these off the chart, and calculating the reorder level, is a standard Paper 1 quantitative task.

$\text{Reorder level} = (\text{Daily usage} \times \text{Lead time}) + \text{Buffer stock}$

Two opposite philosophies sit behind stock control. Just-in-time (JIT) holds almost no stock — materials arrive exactly when production needs them, so buffer stock is near zero. It slashes holding costs, frees up cash and reduces waste and obsolescence, but it leaves the firm exposed if a single delivery fails, so it demands reliable suppliers, accurate demand forecasts and close supplier relationships. Just-in-case (JIC) does the reverse — deliberately holding large buffer stocks so that production and sales continue even if supply is disrupted or demand spikes. It protects against stockouts but ties up working capital and raises the costs of storage, insurance and obsolescence. The choice is really a trade-off between the cost of holding too much stock and the cost of holding too little.

Should a firm produce a component itself ('make') or buy it in from an external supplier ('buy', i.e. outsource)? The quantitative test compares the cost to make against the cost to buy. Making a component in-house usually carries a fixed set-up cost (dedicated machinery, tooling) plus a variable cost per unit, so cost to make = fixed cost + (variable cost per unit × quantity). Buying avoids the fixed cost but pays a set price per unit, so cost to buy = price per unit × quantity. Because making carries a fixed cost, buying is normally cheaper at low volumes and making becomes cheaper once volume is high enough to spread that fixed cost — the crossover is the break-even quantity where the two costs are equal. The numbers, though, are only the start: quality control, protection of proprietary technology, supplier reliability, flexibility and whether the part is core to the business all shape the final decision.

Because 5.6 is a quantitative topic, our marking engine assesses these answers with IB Business Management M (method) and A (accuracy) conventions rather than the essay-style AO bands. An M mark rewards the correct method — the right formula with the right figures substituted in — even if a slip earlier in the working feeds a wrong number into it (follow-through). An A mark rewards the accurate final value WITH its unit. Interpretation marks reward a valid, context-linked comment on what the numbers show. Watch how the marks below attach to method, to accurate values with units, and to a supported interpretation.

These planning tools sit at the heart of the operations unit and connect outward. Capacity utilisation links to break-even and to costs and revenues, because spreading fixed costs over more units is what lowers average cost. Stock control and JIT/JIC feed into lean production and quality management, and into the cash-flow and working-capital ideas from the finance unit — a firm drowning in stock is a firm short of cash. Make-or-buy connects to growth, outsourcing and the firm's core competencies. Master the habit built here — pick the right formula, substitute carefully, attach the unit, then interpret in context — and you have the template that earns marks on every calculation-and-comment question in the course.