Key Concept - Comparative Advantage

While an absolute advantage in an endeavor refers to the ability to produce at the lowest cost or using the least amount of resources; a comparative advantage is the ability to produce at a lower opportunity cost.

An example: Suppose that two castaways on a desert island gather both fruit and grain, which they then share equally between them. Suppose that Castaway A can gather more fruit per hour than Castaway B, and therefore has an absolute advantage in this good. Nonetheless, it may well make sense for A to leave some fruit-gathering to B. This is because it is possible that B gathers fruit slightly slower than A, but gathers grain extremely slowly.

One needs to look at comparative advantage rather than absolute advantage, to discover how A and B can each best allocate their effort. If A's initial advantage over B in grain-gathering is greater than his or her advantage in fruit-gathering, then fruit-effort should be transferred from A to B, to the point where A's comparative advantages in the two goods are equal. Thus it may be rational for fruit to flow from B to A, despite A's absolute advantage.