Endogenous growth theory
A hypothesis, put forward by Paul Romer, that economic growth does not simply arise from exogenous factors (such as the creative insights of inventors) but also from government policies, such as investment in research and development and laws that protect intellectual property. Gordon Brown, Britain’s former prime minister, was mocked for referring to “post-neoclassical endogenous growth theory” in a speech. Mr Romer’s work earned a Nobel prize, but economists still don’t fully understand how and why economies grow.