Public agricultural research has been conducted in Africa for decades. While many studies have examined its aggregate impacts, few have investigated how it affects the poor. This paper helps fill this gap by applying a new procedure to explore the ex post impacts of improved maize varieties on poverty in rural Ethiopia. Plot-level yield and cost changes due to adoption are first estimated using instrumental variable and marginal treatment effect techniques where possible heterogeneity is carefully accounted for. A backward derivation procedure is then developed to link treatment effect estimates with an economic surplus model to identify the counterfactual household income that would have existed without improved maize varieties. Poverty impacts are finally estimated by exploiting the differences between observed and counterfactual income distributions. Improved maize varieties have led to a 0.8-1.3 percentage drop of poverty headcount ratio and relative reductions of poverty depth and severity. However, poor producers benefit the least from adoption due to the smallness of their land holdings.JEL classifications: I32, O33, Q16, Q18

Agricultural extension programs have changed significantly over the past four decades. What has changed and why? Have these changes affected adoption of innovations by farmers? What if anything should policy makers and extension agencies do differently, particularly in developing countries? Structural changes in agriculture, new types of agricultural technologies, tight public budgets, efforts to decentralize government, and emerging information and communication technologies (ICT) have led to pluralistic and, in some cases, lower‐cost extension and advisory services that combine public and private mechanisms for financing and implementing extension activities. Farmer groups and virtual networks play a growing role in technology diffusion, and extension services can exploit these networks using the latest ICT approaches.

Potato farmers in Ecuador rely on chemical inputs to manage pests and optimize yields. Integrated pest management techniques lower production costs, reduce pesticide exposure, and improve long-term agricultural sustainability. Public extension does not, however, exist in Ecuador, and cost-effective means of communicating complex messages to producers are needed. We analyze cost-effectiveness of alternative dissemination methods, including farmer field schools (FFS), field days, pamphlets, and word-of-mouth transmission. Field days and pamphlets have strong impacts on adoption, especially considering their low costs. FFS are effective, but expensive. Evidence also indicates significant diffusion from FFS to non-FFS farmers, indicating high complementarity across methods.

This paper reviews and compares the most common approaches used to evaluate public agricultural research investment. Ex post studies fall into two major groups: (a) consumer and producer surplus analyses, estimating average rates of return to research, and (b) production function analyses, estimating marginal rates of return to research. Ex ante studies fall into four groups: (a) those using scoring models to rank research activities, (b) those employing benefit‐cost analysis to establish rates of return to research, (c) those using simulation models, and (d) those using mathematical programming to select an optimal mix of research activities.

A procedure is developed and applied for predicting ex ante impacts of agricultural research on aggregate poverty, using as an example the poverty-reducing impact of peanut research in Uganda. Market-level information on economic surplus changes is combined with a procedure for allocating income changes to individual households. Characteristics of farmers that affect their likelihood of technology adoption are used to create a technology adoption profile. Associated changes in poverty resulting from adoption are computed using poverty indices. Predicted income changes at the household level are aggregated to the market level and reconciled with calculations of economic surplus changes. Copyright 2007, Oxford University Press.

This study examines the cost-effectiveness of alternative methods for diffusing integrated pest management practices in Bangladesh. Methods compared include farmer field schools, field days, and extension agent visits. Farmer field school participants were more likely to adopt integrated pest management practices than recipients of messages from field days and agent visits. However, due to lower costs per participant, field days were the most cost-effective means for stimulating adoption of simpler practices and extension agent visits were the most cost-effective for extending more complex practices.

Public support for integrated pest management (IPM) is derived in part from concerns over food safety and the environment, yet few studies have assessed the economic value of health and environmental benefits of IPM. An approach is suggested for such an assessment and applied to the Virginia peanut IPM program. Effects of IPM on environmental risks posed by pesticides are assessed and society's willingness to pay to reduce those risks is estimated. The annual environmental benefits of the peanut IPM program are estimated at $844,000. The estimates of pesticide risks and willingness to pay can be applied elsewhere in economic assessments of IPM.

Adoption of improved crop varieties can lead to multiple benefits to farm households, including increased productivity, incomes, and food consumption. However, possible impacts of adoption on child nutrition outcomes are rarely explored in the literature. This article helps bridge this gap through an impact assessment of the adoption of improved maize varieties (IMVs) on child nutrition outcomes using a recent household survey from rural Ethiopia. The conceptual linkage between IMV adoption and child nutrition is first established using an agricultural household model. Instrumental variable estimation suggests the overall impacts of adoption on child height-for-age and weight-for-age z-scores to be positive and significant. Quantile instrumental variable regressions further reveal that such impacts are largest among children with poorest nutrition outcomes. Finally, by combining a decomposition procedure with system of equations estimation, it is found that the increase in own-produced maize consumption is the major channel through which IMV adoption affects child nutrition.JEL classifications: I15, O33, Q16, Q18