Some productivity measures area analyzed. The emphasis is on concepts, limitations and on some empirical results. Software is not discussed. The productivity measures are classified in optimized, whenever obtained by an optimization procedure, and not optimized, as yield, labor productivity and total factor productivity (ptf). The work shows when yields and total factor productivity say the same thing to conclude that this is possible only in a primitive agriculture where labor and land are the only factors of production used. This type of agriculture is present only in backward regions of Brazil. Hence yield, except in this situation, is a poor measure of profitability. Empirical works show that the development of Brazilian agriculture follows a path of land or total resource saving.