Final answer:
Sunk costs and transaction costs are not considered in a differential analysis for a make-or-buy decision.
Step-by-step explanation:
In a make-or-buy decision, certain costs are not considered in a differential analysis. These costs include sunk costs, which are costs that have already been incurred and cannot be recovered. Sunk costs should be disregarded when making current decisions. Additionally, transaction costs, which involve the use of resources such as time and effort to make a decision, are also not typically considered in the analysis.