Such growth, moreover, is often (though not always) correlated with a broad set of social indicators, including poverty reduction, which together describe a more inclusive development path. This path does not emerge spontaneously, however, and even after a period of rapid growth, countries can get stuck or fall back. An important part of the early development policy debate focused on how to quickly raise the share of investment in national income to a level that would trigger a virtuous circle of rising productivity, increasing wages, technological upgrading and social improvements. The required investments are often closely connected, depend on the reaching of a minimum scale to be efficient and may become profitable only over a long period of time.