Poverty statistics and their comparability could also be improved by greater harmonization of criteria, such as those for calculating poverty lines. The absence of this information also precludes analysis of labour earnings or of the impacts of government transfers and taxes on household welfare. The debate about relevant capabilities and the best way to measure equality in these has been wide-ranging (see, among others, Nussbaum, 2001, Robeyns, 2005), but remains open.