To each according to his contribution is a principle of distribution considered to be one of the defining features of socialism. It refers to an arrangement whereby individual compensation is reflective of one's contribution to the social product (total output of the economy) in terms of effort, labor and productivity. This is held in contrast to the method of distribution and compensation in capitalism, where those who own private property receive unearned income in the form of interest, rent, or profit by virtue of ownership irrespective of their contribution to the social product.