But while large shares of total tax revenues can be spent on transfers, such a correspondence needs not (and usually does not) hold in every period as taxes finance non-benefit expenditures as well. Likewise, current benefit expenditure can be financed through non-tax sources, notably borrowing. To the extent that the existence of taxes and benefits causes changes in market prices and household behaviour, redistribution policies have an influence on pre-tax benefit market incomes (and economic welfare) which is not captured by looking at the amounts of taxes and benefits alone. There is a voluminous literature on the consequences of tax or benefit reforms that alter incentives to earn and declare taxable income (e.g., Giertz et al., These indirect (or “second-round") effects of redistribution policies are at the heart of debates concerning their cost-effectiveness.