The paper describes the problems encountered in appraising the incidence of a tax, in particular, that of the VAT. The futility of attempting to evaluate the incidence of entire tax systems is outlined: limitations on data and severe conceptu~l and methodological problems render the answers obtained quite unreliable. The results of studies of tax incidence that express tax burdens as effective tax rates can be no bettEr than the incidence assumptions and data underlying them.