Operations management: By which single action can the production cost per unit be most directly reduced, without increasing the quantity of inputs used?

Introduction / Context:
In operations and industrial engineering, reducing unit cost is fundamentally about improving productivity. Productivity rises when an organisation obtains more useful output from the same level of input, thereby spreading fixed and variable components more efficiently across each unit produced.

Given Data / Assumptions:

• Inputs (labour hours, machine time, materials, energy) are held constant for fair comparison.
• Output is measured as conforming units (good quality) shipped.
• Quality level and safety are maintained; no rework is hidden.

Concept / Approach:
Unit cost = Total cost / Units produced. If total inputs and their costs are unchanged, but output increases, the denominator grows while the numerator stays the same, so the cost per unit falls. This can result from better methods, higher overall equipment effectiveness, reduced changeover time, or yield improvement.

Step-by-Step Solution:

Verification / Alternative check:
Check contribution margin. If selling price and variable costs per input are unchanged, more good units per input hour increase contribution per hour and lower cost per unit—verified in standard CVP analysis.

Why Other Options Are Wrong:

• Producing more with increased inputs: total cost rises proportionally or more; unit cost may not fall.
• Eliminating all idle time regardless of cost: may require excessive investment; could raise cost per unit.
• Minimising waste even if throughput falls: extreme conservation can decrease output, raising unit cost.

Common Pitfalls:
Confusing total cost reduction with unit cost reduction; neglecting quality (scrap and rework lower effective output).

Final Answer:
Producing more with the same inputs