Source: Question 9b, p 61, Principles of Microeconomics, 7 Ed, 2014, by N Gregory Mankiw
= Question 8b in Principles of Microeconomics, 4 Ed, 2008
9. Are the following statements true or false? Explain in each case.
b. “Certain very talented people have a comparative advantage in everything they do.”
Answer: b. False; it is not true that some people have a comparative advantage in everything they do. In fact, no one can have a comparative advantage in everything. Comparative advantage reflects the opportunity cost of one good or activity in terms of another. If you have a comparative advantage in one thing, you must have a comparative disadvantage in the other thing.
Abbreviate comparative advantage as CA. Mankiw's question above motivates the titled one.
E.g., suppose in a 3-person economy: person A's CA is cooking and person B's foraging, yet person C does nothing.