Economic impact assessment in pest risk analysis

According to international treaties, phytosanitary measures against introduction and spread of invasive plant pests must be justified by a science-based pest risk analysis (PRA). Part of the PRA consists of an assessment of potential economic consequences. This paper evaluates the main available techniques for quantitative economic impact assessment: partial budgeting, partial equilibrium analysis, input output analysis, and computable general equilibrium analysis. These techniques differ in width of scope with respect to market mechanisms (relationships between supply, demand, and prices), and linkages between agriculture and other sectors of the economy. As a consequence, techniques differ in their ability to assess direct and indirect (e.g. economy-wide) effects of pest introduction. We provide an overview of traits of the available methods to support the selection of the most appropriate technique for conducting a PRA. Techniques with a wider scope require more elaborate data, and greater effort to conduct the analysis. Uncertainties are compounded as methods with greater scope are used. We propose that partial budgeting should be conducted in any risk assessment, while more sophisticated techniques should be employed if the expected gains in insight outweigh the costs and compounded uncertainties.