Which method focuses only on direct materials as product costs?

Throughput costing, also known as super-variable costing, focuses solely on direct materials as product costs. This method emphasizes the importance of maximizing production throughput by considering only the costs associated with direct materials in the calculation of product cost. This approach captures the contribution margin by deducting only direct material costs from sales revenue, which allows companies to concentrate on the cash flow generated from their operations and the profitability of their product lines.

In contrast to throughput costing, activity-based costing allocates overhead costs to products based on the activities that drive those costs, leading to a more comprehensive view that includes various indirect costs. Standard costing employs predetermined costs for direct materials, direct labor, and overhead, which provides a framework for measuring performance against these standards. Absorption costing, on the other hand, incorporates all manufacturing costs — direct materials, direct labor, and both fixed and variable overhead — into product costs, which does not align with the focus on direct materials alone.

Thus, the reason throughput costing is the correct answer lies in its unique identification of product costs as limited strictly to direct materials, providing a distinct perspective on cost management and profitability.