On the marginal cost of public funds: the implications of charitable giving and warm glow

This paper highlights the important impact of charitable giving and warm glow on the identification of the marginal cost of public funds (MCF). We employ the warm glow model of charitable giving to describe taxpayer behaviour, whereas we employ the standard model to evaluate social welfare. We first identify the impact theoretically. Then we conduct simulations to quantify its size numerically. The results of our numerical simulations show that the standard model underestimates the magnitude of MCF by at least 10 per cent. Our work suggests that adopting a non-welfarist social welfare function can make a significant difference to the identification of MCF.