law of diminishing marginal returns

The law of diminishing marginal returns states that as the number of inputs to a production process increase, the marginal product (i.e. the additional output garnered from adding one extra unit of input) eventually reaches a point of diminishing returns – that is, eventually the additional output generated by the added input will decrease. This concept can be visualized as the diminishing slope of a graph that plots the output vs. input. This is due to the fact that given limited resources, adding more and more of one input often causes that input to be more inefficiently used, as the other inputs are not available in sufficient quantities to maximize the output generated.