An outward shift of the PPC results from growth of the availability of inputs, such as physical capital or labour, or from technological progress in knowledge of how to transform inputs into outputs.

What causes the PPC to shift outward?

Shifts in the production possibilities curve are caused by things that change the output of an economy, including advances in technology, changes in resources, more education or training (that's what we call human capital) and changes in the labor force.

Why is PPF bent outward?

So in the last blog we concluded that it is bent outward because of the imperfect substitute-ability of resources which led the central solution having appropriate allocation of inputs to their productive sectors let an outcome which had higher benefits as compared to corner solutions.