Production processes: just in time (JIT).

The idea

Just in time (JIT) is a stock control method where materials and components arrive exactly when needed for production, so minimal buffer stock is held. A car plant might receive seats each morning for that day's build, rather than storing weeks of seats. JIT reduces storage costs, frees working capital and cuts waste from damaged or obsolete stock, but it depends on reliable suppliers, accurate demand forecasting and efficient logistics. Any delay, quality failure or transport disruption can halt production because there is little safety stock. JIT therefore links directly to production processes: it supports lean, continuous flow and can reduce lead times, but it raises vulnerability to supply shocks.

What earns the marks

• Defines JIT as arranging deliveries so that stock arrives just as it is needed for production, with minimal or no buffer stock held.
• Explains how JIT operates: close scheduling with suppliers, frequent small deliveries, and production triggered by actual demand rather than stockpiling.
• Analyses benefits such as lower storage and insurance costs, less working capital tied up in stock, reduced waste from deterioration or obsolescence, and a smaller factory footprint.
• Analyses drawbacks such as vulnerability to late deliveries, supplier quality problems, transport disruption, and the need for accurate demand forecasting and strong supplier relationships.
• Applies JIT to a context, for example a restaurant receiving fresh ingredients daily or a manufacturer receiving components for same-day assembly.
• Evaluates suitability: JIT may suit businesses with reliable suppliers and predictable demand, but may be risky where demand is volatile or supply chains are fragile.

Common mistakes and how to put them right

• Confusing JIT with simply keeping no stock at all.

  Put it right: JIT aims for stock to arrive as needed, so very low buffer stock may still exist.

• Assuming JIT always lowers total costs.

  Put it right: JIT can raise ordering and transport costs and creates disruption risk if deliveries fail.

• Treating JIT as only a manufacturing technique.

  Put it right: It also applies to service businesses such as restaurants, hospitals and retailers.

• Ignoring the role of suppliers.

  Put it right: JIT requires dependable, often local or closely coordinated suppliers.

Exam tips

• When a case study mentions stockholding, storage costs or supplier reliability, consider whether JIT is relevant and explain the link explicitly.
• For analysis, use a chain of reasoning: JIT reduces buffer stock, which lowers storage costs, which frees cash for other uses.
• For evaluation, weigh benefits against risks and reach a supported judgement about whether JIT is suitable for the specific business context.
• Use business terminology accurately, such as buffer stock, lead time, working capital and supply chain, to strengthen responses.