Activity — Cost Driver
| Activity | Cost Pool | Activity Cost Driver | Total Driver Quantity | Cost per Driver | Product X Usage | Product Y Usage | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | Machine Setup | $200,000 | Number of setups | 200 setups (100 for X, 100 for Y) | $1,000 per setup | 100 setups = $100,000 | 100 setups = $100,000 | | Purchasing | $100,000 | Number of POs | 500 POs (100 for X, 400 for Y) | $200 per PO | 100 POs = $20,000 | 400 POs = $80,000 | | Quality Control | $150,000 | Inspection hours | 1,500 hours (500 for X, 1000 for Y) | $100 per hour | 500 hrs = $50,000 | 1,000 hrs = $100,000 | | | | | | | $170,000 | $280,000 | | Overhead Per Unit | | | | | $170,000 / 10,000 units = $17 | $280,000 / 100 units = $2,800 |
Think of an activity like a vending machine. The machine (the activity) has fixed costs (rent, electricity) and variable costs (the products inside). The "cost driver" is the button you press. Each time you press the button (the driver), the machine dispenses a product, and the machine’s total cost of goods sold increases. More button presses = higher total cost. activity cost driver
| Feature | Traditional Cost Driver | Activity Cost Driver | | :--- | :--- | :--- | | | One driver for all overhead | Multiple drivers per activity | | Causality | Assumes all costs vary with volume | Recognizes that many costs vary with complexity and transactions | | Accuracy for Diverse Products | Low (often distorts costs) | High | | Example Driver | Direct labor hours | Number of setups, number of purchase orders, number of engineering change orders | | Activity | Cost Pool | Activity Cost
Whether you are a startup founder, a production manager, or a CFO, your mission is clear: identify your key activities, find the factors that truly drive their costs, and manage those drivers ruthlessly. In the end, profitability is not just about what you earn; it is about what you understand. And activity cost drivers are the key to that understanding. Each time you press the button (the driver),
Without correct drivers, a company flies blind, potentially subsidizing unprofitable products while starving profitable ones. With them, management gains x-ray vision—seeing exactly where value is created and where it is wasted.