This chapter reviews definitional issues that arise in assessing the extent of, and change in, poverty in western industrialized countries, including the choice of resource, level of poverty line and appropriate adjustments for the size and type of the income-sharing unit. The chapter also reviews the existing empirical evidence and presents estimates using the Luxembourg Income Study database. The first-order iimpact of the public sector suggests that countries with similar rates of market income poverty can have very different poverty rates once taxes and transfers have been received. Cross-national evidence on longitudinal aspects of poverty suggests that much remains to be learned about the patterns of intra- and intergenerational poverty mobility and their covariates.
