Writers after Coase have referred to the authority structure of the firm as a "visible hand" that works in combination with Smith's invisible hand. The everyday fact that employers exercise power over their employees - not news to most employees - had been a central theme in Marx's economics, but it was (and generally continues to be) overlooked by most neoclassical economists. Early in his studies Coase noted the similarity between the hierarchical organization of capitalist firms, with their reliance on command relations, and the then-existing system of centralized economic planning in the Communist countries, where production was carried out in accordance with orders from higher authorities and where market competition played little role.