Agricultural policies and food systems: Priorities for indicator development

Existing indicators of agricultural protection and support were developed primarily to gauge the market and welfare effects of government policies. They have shed light on a wider range of impacts through their use in economic models and empirical analysis. The rising scale of support to agriculture globally, and continued reliance on market distorting policy instruments, make this work as important as ever. Deeper investments are nonetheless needed to address heightened concerns about the spill-over impacts of agricultural policies on the performance of food systems, in particular with respect to food security and nutrition, rural livelihoods, resource use and the environment, and global emissions. A first area for development is improved measures of policies to correct agriculture's externalities. A priority here is to develop a carbon tax equivalent of sectoral mitigation efforts. A second area is to provide a clearer delineation of government spending on private versus public goods. This would make a valuable contribution to a ‘repurposing’ agenda that seeks to identify how agricultural budgets can be spent more effectively, as well as the scope for transferring resources to wider social priorities, such as public health and climate action.     

Notes on marriage markets with weak externalities

We consider marriage markets with externalities. We focus on weak externalities, that is, markets in which each agent is primarily concerned about her partner. We formalize and prove the claim that weak externalities are not so significant in the marriage market: in this case, the ω-core and the α-core coincide and are both nonempty. In addition, we show that, if we allow agents to block matchings without changing their mate, the results do not longer hold.     

Transnational crimes: how nations should cooperate and why they don't*

Chain-form crime partnerships and intelligence sharing by national authorities to detect cross-border partners create multiple externalities in the combat against transnational crimes and illicit trafficking. Cooperative enforcements that minimize global harms prioritize the country with lower intelligence production and/or superior detection capability. In equilibrium, as in practice, national enforcements are underbudgeted and might prioritize the wrong side – predominantly the high-budget, high-harm country. Governments might not share intelligence out of fear of importing enforcement burden, and harmonizing criminal sanctions alone might not be effective. Shocks on crime deterrence in a target country are first absorbed by source countries, implying weaker horizontal crime transfer effects than projected.     

The role of vaccine effectiveness on individual vaccination decisions and welfare

This paper examines a theoretical model designed to characterize a static, individual vaccination decision environment. I identify and characterize both equilibrium and socially optimal vaccination behavior and determine how this behavior changes as the effectiveness of the vaccine changes. I also evaluate the individual and social welfare implications of a change in vaccine effectiveness. I find that under certain conditions, an increase in vaccine effectiveness can decrease the number of agents vaccinating in equilibrium due to the positive external effects of vaccination. Notably, it is also possible for individual and total welfare to decrease. This is an undesirable, and perhaps unexpected, consequence of better vaccines. Fortunately, welfare at the social optimum always increases as vaccine effectiveness increases. However, equilibrium behavior often falls short of the social optimum due to the positive externalities created by vaccinating.