For an entire economy, the production possibilities frontier is represented as what shape?

The production possibilities frontier (PPF) is typically represented as a bowed-out shape, which reflects the principle of increasing opportunity costs. This shape arises because resources are not equally efficient in the production of all goods. As an economy shifts resources from producing one good to another, it experiences varying degrees of efficiency with which these resources can be allocated.

Specifically, when the economy focuses on producing more of one good, it increasingly has to give up larger amounts of the other good because resources that are better suited for the first good are not as effective in producing the second good. This leads to a curve that is concave to the origin, illustrating that the opportunity cost of producing more of one good increases as production shifts more heavily towards it. This characteristic helps to explain why the economy cannot produce in a straight line or in a rectangular shape, as those representations would imply a constant or non-increasing opportunity cost which does not align with the reality of resource allocation.