Managing stock: ● interpretation of bar gate stock graphs ● the use of…

The idea

Managing stock efficiently is vital for business liquidity. A bar gate stock graph visually tracks inventory levels over time. Key features include the maximum stock level, minimum stock level (buffer stock), and the reorder level (the point at which new stock is ordered). The lead time is the delay between ordering and receiving stock. For example, a retailer might reorder when stock falls to 50 units, expecting delivery before hitting their 10-unit buffer. Alternatively, Just in Time (JIT) stock control eliminates buffer stock entirely. Materials arrive exactly when needed for production, reducing storage costs and waste. However, JIT requires highly reliable suppliers and leaves the business vulnerable to delivery delays or sudden demand spikes.

What earns the marks

• Identify maximum stock, minimum (buffer) stock, and reorder levels accurately from a bar gate graph.
• Calculate lead time by measuring the horizontal time gap between placing an order and receiving the inventory.
• Explain that JIT reduces warehousing costs, security expenses, and the risk of stock becoming obsolete or perishing.
• Evaluate JIT by discussing the risk of halting production entirely if a supplier fails to deliver materials on time.

Common mistakes and how to put them right

• Confusing the reorder level with the reorder quantity.

  Put it right: The reorder level is the stock level that triggers a new order, whereas the reorder quantity is the actual amount of stock purchased.

• Assuming JIT simply means ordering stock quickly.

  Put it right: JIT means ordering stock so it arrives exactly when needed for production, deliberately holding zero buffer stock.

• Misreading the lead time on a bar gate graph.

  Put it right: Measure lead time horizontally along the x-axis from the reorder point to the vertical line showing the arrival of new stock.

Exam tips

• When interpreting a bar gate graph, use a ruler to trace the reorder level across to the y-axis to ensure accurate readings.
• If asked for a disadvantage of JIT, focus on the vulnerability to external shocks like transport strikes or sudden surges in customer demand.
• Link the reduction of buffer stock in JIT directly to improved cash flow, as less working capital is tied up in inventory.