Final answer:
Sunk costs should be treated as irrelevant to short-run decision making because they cannot be changed or recovered.
Step-by-step explanation:
When making short-run decisions, you should treat your sunk costs as irrelevant. Sunk costs are costs that have already been incurred and cannot be recovered. They are not relevant to future decision-making because they cannot be changed or undone. Therefore, it is best to focus on the potential future benefits or liabilities of a decision rather than past costs.