Who makes trade-offs?
Opportunity Cost
Is the most desirable alternative you gave up in a trade-off
What is the main idea of opportunity cost?
Because resources are scarce we must make choices or trade-offs. The 2nd most desirable thing lost by making this decision is the opportunity cost.
Thinking at the Margin
When you are unsure of the opportunity cost and must decide how much more or less of a unit to use
Trade-Off
All the alternatives that we give up whenever we make make a choice