In economics 'unearned income' has different meanings and implications depending on the theoretical framework used. To classical economists, with their emphasis on dynamic competition, income not subject to competition, mainly income from land titles, are 'rents' or unearned income. According to certain conceptions of the Labor Theory of Value, it may refer to all income that is not an immediate result of labor. In a neoclassical frame, it may mean income not attributed to the normal or expected returns to a factor of production. Generally it may refer to windfall profits, such as when population growth increases the value of a plot of land.