Suppose Congress is considering raising the top federal marginal tax rate from 35% to 40%. Senator Jones believes the elasticity of taxable income is large. Senator Smith believes the elasticity of taxable income is small. (Both believe the elasticity is positive.) The Congressional Budget Office estimates the effects of the tax proposal using each Senator's assumptions. (i) Will the estimates of additional revenue from the tax increase be larger or smaller under Senator Jones's assumptions, compared to Senator Smith's assumptions? (ii) What about estimates of the efficiency costs of the tax increase: which set of assumptions leads to the higher estimate?

Solution-

According to Senator Jones, the elasticity of taxable income is larger, which means that due to a certain percentage rise in taxes, the taxable income rises by a greater percentage. Also, according to Senator Smith, the elasticity of taxable income is small, which means that due to a certain percentage rise in taxes, the taxable income rises by a smaller percentage.

(I) Under Senator Jones assumptions, due to rise in taxes, the taxable income has risen considerably as compared to Senator Smith assumptions. Thus the estimates of additional revenue from the tax increase will be larger under Senator Jones assumptions, compared to Smith's assumptions.

(ii) Since under Senator Jones assumptions, elasticity of taxable income is large. So due to rise in taxes, there is a significant proportional rise in taxable income under Jone's assumptions compared to Senator Smith assumptions. Thus the costs of the tax increase is borne more under Senator Jones assumptions, compared to Smith's assumptions.