Relative-Income Effects and the Appropriate Level of Public Expenditure

The welfare of an individual depends not only on his own income but also on his income relative to that of others. A private good that he consumes yields him (intrinsic consumption and relative-income) utilities, but also imposes external costs on others through the relative-income effects. Expenditure on public goods not only produces intrinsic consumption utilities but also indirect relative-income utilities by reducing private expenditure. Since this indirect effect is unlikely to be adequately accounted for, the "optimal" level of public expenditure estimated by the conventional SMRS 3 MRT is really suboptimal.