Optimal tax in his article titled "Using Elasticities to Derive Optimal Income Tax Rates" derives a formula for optimal level of income tax using the both compensated and uncompensated elasticities. Saez writes the tradeoff between equity and efficiency is a central consideration of optimal taxation, and implementing a progressive tax allows the government to reallocate their resources where they are needed most. However, this deters those of higher income levels to work at their optimal level. Saez decomposes the marginal effects of a tax change into mechanical, behavioural and welfare effects, as follows: The sum of these effects should be zero at
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