Measuring Lifetime Poverty

This paper presents an axiomatic framework for measuring life time poverty over multiple periods. For an individual, we argue that lifetime poverty is influenced by both the snapshot poverty of each period and the poverty level of the "permanent" lifetime consumption; it is also influenced by how poverty spells are distributed over the life time. Two obvious candidates for aggregation are to aggregate over time and then across individuals, or vice versa. For a society, we consider a path-independence requirement to make these two approaches of aggregation consistent. We axiomatically characterize classes of lifetime poverty indices and derive dominance conditions of poverty orderings for both individual and societal lifetime poverty measurements.