How does attrition affect estimates of persistent poverty rates? The case of EU-SILC.

Over the last decade and through its Open Method of Coordination, the EU has agreed a set of common objectives for monitoring and measurement of social protection and social inclusion, together with a set of indicators to assess national and EU progress towards these goals. Among the primary indicators of social inclusion is the persistent at-risk-of-poverty rate, defined as the proportion of persons in a country who are at risk of income poverty in the current year and who were at risk of income poverty in at least 2 of the preceding 3 years. Evidence about poverty persistence is an important complement to information about poverty prevalence at a point in time: it is widely agreed that poverty is worse for an individual, the longer he or she experiences it. Eurostat derives estimates of persistent at-risk-of-poverty rates using samples from the longitudinal component of EU-SILC in which the fortunes of individuals are tracked over 4 consecutive years. Because not all of the individuals present in the first sample year provide 4 years of income data ? there is attrition ? estimates of persistent at-risk-of-poverty measures may not be reliable. In this chapter, we analyse the extent to which this is the case, and how the potential problems vary across EU Member States.