This article is a contribution to the literature studying the possible tools for combating poverty. After tracing the main lines of «Making work pay» (Mwp) schemes, there is an analysis of the main features of Earned income tax credit (Eitc). The aim is to clarify how Eitc, which aims to redistribute wealth, also determines responses from economic agents that have a strong effect on efficiency. The work brings out how, on the basis of the theory of optimum taxation, the Mwp schemes can have effects in terms of efficiency in two different ways. The first concerns the risks linked to the creation of inefficiency traps (inactivity, unemployment, poverty), while the second concerns the contrasting effects of Eitc in relation to the extensive margin (being part of the labour market or not) and the intensive margin (variation in hours worked). The possibility of being able to reconcile redistribution and efficiency is still an open debate, useful for guiding the preparation of optimum policies of income support.only subscribers can see the full article