AQA A-Level Business (7132)

## Learning Outcomes

- Understand what inventory and supply chains are and why they affect operational performance
- Identify the main parts of an inventory control chart, including buffer stock, lead time, re-order level and re-order quantity
- Calculate and interpret re-order levels and economic order quantity (EOQ)
- Explain the trade-offs between Just in Time (JIT) and Just in Case (JIC) stock control
- Analyse factors that affect how much inventory a business should hold
- Evaluate supplier choice using both operational and financial evidence
- Structure strong evaluative answers on inventory and supply chain decisions in context

## AQA A-Level Business (7132) Syllabus

For the AQA A-Level Business (7132), you are expected to understand inventory and supply chain decisions within operational management, with a focus on the following syllabus points:

- Know what **inventory** includes, including raw materials, work-in-progress and finished goods
- Identify and interpret the main features of an **inventory control chart**
- Explain **lead time**, **buffer stock**, **re-order level** and **re-order quantity**
- Understand how businesses decide how much inventory to hold and order
- Apply the **EOQ** formula to inventory decisions
- Explain the difference between **Just in Time (JIT)** and **Just in Case (JIC)**
- Analyse factors affecting **supplier choice**, such as cost, quality, reliability and flexibility
- Evaluate how inventory and supply chain decisions affect costs, cash flow, customer service, flexibility and dependability

## Test Your Knowledge

_Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, look more closely at that area during your revision._

1. What is the difference between buffer stock and re-order level?
2. How does lead time affect the amount of inventory a business should hold?
3. What does EOQ calculate?
4. Why might the cheapest supplier not be the best supplier?
5. How do JIT and JIC differ?

## Introduction

Inventory and supply chain decisions sit at the centre of operational performance. If a business holds too much stock, money is tied up, storage costs rise and products may become outdated or spoiled. If it holds too little, it may run out, lose sales, stop production and damage customer satisfaction.

This topic is a common source of application and evaluation questions because there is rarely one perfect answer. A business must balance efficiency against security of supply. A supermarket, airline parts supplier and fashion retailer may all need very different stock policies.

> **Key Term: inventory**
> The stock held by a business, including raw materials, work-in-progress and finished goods.

### Inventory control and why it matters

Inventory control is about deciding when to order stock, how much to order, and how much extra stock to keep for safety. Good control helps a business match supply to demand.

The three main forms of inventory are:

- **Raw materials** such as flour in a bakery
- **Work-in-progress** such as part-built cars on a production line
- **Finished goods** such as completed trainers ready for sale

Holding high inventory levels has clear benefits. Customer demand can be met quickly, sudden rises in sales can be handled, and production is less likely to stop because materials are missing. Businesses may also gain discounts from bulk buying.

However, high inventory also creates costs:

- storage and warehousing costs
- insurance and security costs
- risk of damage, theft or waste
- risk of obsolescence
- cash tied up in stock rather than being used elsewhere

Low inventory reduces these costs, but the risk of shortages increases.

> **Key Term: supply chain**
> The network of organisations and activities involved in moving a product from supplier to final customer.
>
> **Key Term: buffer stock**
> The minimum amount of inventory a business keeps to deal with delivery delays or unexpected increases in demand.

AQA often tests the logic of the inventory control chart. You need to know each feature precisely.

An inventory control chart usually shows:

- stock levels falling over time as inventory is used
- a **re-order level**, where a new order is triggered
- a **lead time**, which is the gap between placing the order and receiving it
- a **re-order quantity**, which is the amount delivered
- a **buffer stock** or minimum stock level for emergencies
  > **Key Term: re-order level**
  > The stock level at which a new order is placed.
  >
  > **Key Term: lead time**
  > The time between placing an order and receiving the stock.
  >
  > **Key Term: re-order quantity**
  > The amount of stock ordered each time inventory is replenished.

A simple relationship to remember is:

- **Re-order level = buffer stock + stock used during lead time**

If the business uses 50 units per week, lead time is 2 weeks, and buffer stock is 100 units:

- stock used during lead time = 50 × 2 = 100
- re-order level = 100 + 100 = **200 units**

This means the business should place an order when stock falls to 200 units.

Worked example:

A drinks company uses 120 bottles per day. Delivery takes 3 days. It wants buffer stock of 90 bottles.

Step 1: Calculate usage during lead time

- 120 × 3 = 360 bottles

Step 2: Add buffer stock

- 360 + 90 = 450 bottles

Step 3: State the answer

- **Re-order level = 450 bottles**

This means once stock falls to 450 bottles, a new order should be placed.

Common student errors:

- confusing **buffer stock** with **re-order level**
- forgetting that stock continues to be used during lead time
- treating re-order quantity as the same as re-order level
  > **Test Tip:** In calculation questions, label each step clearly. Examiners reward method marks, so write out usage during lead time before giving the final re-order level.

### EOQ, JIT and JIC

The **Economic Order Quantity (EOQ)** helps a business estimate an order size that minimises the combined costs of ordering and holding inventory.

> **Key Term: Economic Order Quantity (EOQ)**
> A calculation used to find an order size that helps minimise total ordering and holding costs.

The formula is:

- **EOQ = √((2CoD) / Ch)**

Where:

- **Co** = cost of placing one order
- **D** = annual demand
- **Ch** = annual holding cost per unit

Worked example:

A business has:

- ordering cost per order = £40
- annual demand = 10,000 units
- holding cost per unit per year = £5

Step 1: Substitute into the formula

- EOQ = √((2 × 40 × 10,000) / 5)

Step 2: Multiply the numerator

- 2 × 40 × 10,000 = 800,000

Step 3: Divide by holding cost

- 800,000 / 5 = 160,000

Step 4: Find the square root

- EOQ = √160,000 = **400 units**

So the business should order approximately **400 units each time**.

Interpretation matters. EOQ is useful because:

- ordering too frequently raises administration and delivery costs
- ordering too much raises storage and tied-up cash costs

But EOQ has limits. It assumes demand and costs are fairly stable. Real businesses may face seasonal demand, disruption or sudden price changes.

Common student errors:

- forgetting the square root
- using monthly demand instead of annual demand without checking the data
- assuming EOQ gives the final answer without evaluating business context

A major stock-control choice is **JIT vs JIC**.

> **Key Term: Just in Time (JIT)**
> A stock control approach where inventory arrives only when needed for production or sale.
>
> **Key Term: Just in Case (JIC)**
> A stock control approach where extra inventory is held to protect against disruption or unexpected demand.

A side-by-side comparison helps:

| Feature                 | JIT                                    | JIC                              |
| ----------------------- | -------------------------------------- | -------------------------------- |
| Inventory held          | Low                                    | High                             |
| Storage costs           | Lower                                  | Higher                           |
| Cash tied up            | Lower                                  | Higher                           |
| Risk of stockouts       | Higher                                 | Lower                            |
| Waste/obsolescence      | Lower                                  | Higher                           |
| Dependence on suppliers | Very high                              | Lower                            |
| Best suited to          | Predictable demand, reliable suppliers | Uncertain demand or risky supply |

JIT can improve cash flow and reduce waste. This is especially attractive for firms with expensive stock, limited warehouse space or products that can go out of date.

However, JIT can be risky. A late delivery may halt production or leave shelves empty. That can damage sales, reputation and customer loyalty.

JIC is more secure, but it is more expensive. It may suit businesses where running out of stock is very costly, such as hospitals or firms facing volatile demand.

> **Test Tip:** Evaluation on JIT should never stop at “lower costs”. Add the condition: JIT works best only when suppliers are dependable and demand is reasonably predictable.

### Supplier choice and supply chain performance

Supplier choice is not just a purchasing issue. It affects cost, quality, speed, flexibility and brand reputation.

Key factors in supplier choice include:

- **Cost**: lower prices may improve margins
- **Quality**: poor inputs can create defects, returns and waste
- **Dependability**: late deliveries can cause stockouts or halted production
- **Lead time**: shorter lead times reduce the need for high stock levels
- **Flexibility**: useful if demand changes quickly
- **Capacity**: can the supplier cope with bigger orders?
- **Payment terms**: these affect cash flow
- **Ethics**: unethical sourcing can damage reputation

If poor quality is not dealt with, the effects can spread across the business:

- fewer repeat purchases
- higher costs from returns, repairs and waste
- reputational damage
- falling capacity utilisation if sales drop
  > **Key Term: dependability**
  > The ability to deliver or complete operations on time and as promised.

A cheap supplier may appear attractive, but if deliveries are unreliable, the total cost may rise. The business may face lost sales, emergency delivery charges, overtime, customer complaints and reputational harm.

For a premium brand, supplier quality may matter more than price. For a low-cost retailer, price may be more important, but only if quality remains acceptable. For a business using JIT, reliability and lead time are often more important than the lowest unit price.

Supply chain management is really about trade-offs. A business may reduce costs by using a single overseas supplier, but that raises risk. It may improve resilience by using several suppliers or holding more buffer stock, but that raises cost.

> **Key Term: supply chain resilience**
> The ability of a supply chain to cope with disruption and recover quickly.

Ways to improve resilience include:

- using more than one supplier
- holding extra buffer stock on key items
- choosing suppliers with shorter lead times
- building strong supplier relationships
- improving forecasting and stock monitoring

### How to structure an evaluative answer

For 16-mark or 20-mark operational questions, strong answers follow a clear pattern:

- **On the one hand**: explain the benefits of one approach
- **On the other hand**: explain the costs or risks
- **It depends on**: show which contextual factors change the answer
- **Judgement**: decide which factor matters most in this business

For example, if asked whether a retailer should move to JIT, useful evidence would include:

- current warehousing costs
- supplier reliability
- lead times
- demand predictability
- risk of spoilage or obsolescence
- effect on cash flow
- likely impact on customer service

Non-financial factors also matter:

- reputation
- customer loyalty
- relationships with suppliers
- operational flexibility
- risk of disruption

A good final judgement is specific. Do not say “it depends” and stop. Say what it depends on and which factor is most important. For example: JIT is likely to work for a supermarket with strong data systems and dependable local suppliers, but not for a fashion retailer facing uncertain overseas deliveries.

## Key Point Checklist

_This article has covered the following key knowledge points:_

- Inventory includes raw materials, work-in-progress and finished goods
- A supply chain covers the movement of products from suppliers to final customers
- Buffer stock is the minimum stock held for emergencies
- Re-order level is the stock point at which a new order is triggered
- Lead time is the delay between placing an order and receiving it
- Re-order quantity is the amount ordered each time
- Re-order level depends on usage during lead time plus buffer stock
- EOQ helps estimate an order size that minimises holding and ordering costs
- JIT reduces stockholding costs but increases exposure to disruption
- JIC improves security of supply but raises storage costs and tied-up cash
- Supplier choice should be judged using cost, quality, reliability, lead time and flexibility
- Good evaluation balances efficiency against resilience in the business context

## Key Terms and Concepts

- inventory
- supply chain
- buffer stock
- re-order level
- lead time
- re-order quantity
- Economic Order Quantity (EOQ)
- Just in Time (JIT)
- Just in Case (JIC)
- dependability
- supply chain resilience


Operational decisions - Inventory and supply chains