Laffer curve is simplistic in that it assumes a single tax rate and a single labor supply. Actual systems of public finance are more complex, and there is serious doubt about the relevance of considering a single marginal tax rate. In addition, revenue may well be a multivalued function of tax rate; for instance, an increase in tax rate to a certain percentage may not result in the same revenue as a decrease in tax rate to the same percentage (a kind of hysteresis). Furthermore, the Laffer curve does not take explicitly into account the nature of the tax avoidance taking place.
From each according to his ability, to each according to his needs Marx's terminology), the Soviet Union adapted the formula as: "From each according to his ability, to each according to his work (labour investment)". While liberation theology has sought to interpret the Christian call for justice in a way that is in harmony with this Marxist dictum, many have noted that Jesus' teaching in the "Parable of the Talents" (Matthew 25:14–30) affirms only "TO each according to his ability" (Matt. 25:15), and not "FROM each according to his ability". From each according to his ability, to each according to his needs "From each according to his ability, to each according to