What do combinations outside of the production possibilities frontier represent?

Combinations outside of the production possibilities frontier (PPF) indicate production levels that are currently unattainable given the existing resources and technology. The PPF itself represents the maximum outputs that can be produced with a set amount of resources efficiently allocated. Anything beyond this curve exceeds those capabilities, meaning that the economy or production process does not have enough resources or technology to achieve those levels of output at the current time.

While it is possible that future advancements or increases in resources could allow for production at those levels, as of now, they remain beyond reach. This understanding helps illustrate the concepts of scarcity and opportunity costs which are essential in economics, emphasizing the limits imposed by resources in production scenarios.