Safety nets are noncontributory transfer programs targeted to the poor or vulnerable. They play important roles in social policy. Safety nets redistribute income, thereby immediately reducing poverty and inequality; they enable households to invest in the human capital of their children and in the livelihoods of their earners; they help households manage risk, both ex ante and ex post; and they allow governments to implement macroeconomic or sectoral reforms that support efficiency and growth. To be effective, safety nets must not only be well intended, but also well designed and well...