Adoption and Ex-post Impacts of Improved Cowpea Varieties on Productivity and Net Returns in Nigeria

Cowpea covers the largest area of any grain legume in Africa and is especially important in West Africa where Nigeria and Niger alone account for over 75% of the total cowpea production in the world. Despite successes of international and national cowpea improvement research in the development and release of several improved varieties, there is limited empirical evidence of adoption and ex-post impacts of improved cowpea. Using a nationally representative survey data from a sample of 1,525 cowpea-growing households in northern Nigeria cultivating over 2,500 cowpea plots, we assess the adoption and impacts of improved cowpea varieties on cowpea yields, net returns and production costs. We apply a control function approach and propensity score matching models to estimate the causal effects of adoption of improved cowpea varieties . Our results show that 38% of the cowpea plots were planted with improved varieties, and cowpea yields, net returns and production costs increase significantly with the adoption of improved cowpea varieties. Adoption of improved cowpea varieties is associated on average with 26% yield gains, 61% increase in net returns and 14% increase in production costs. We also show that farmers who have a lower propensity to adopt improved cowpea varieties also face higher costs of production.     

Returns to wheat breeding research in Nepal

Returns to investment in wheat breeding research in Nepal were estimated for two periods: (1) the Green Revolution period (1960–1990), when modern semidwarf wheat varieties first appeared and spread throughout the country, and (2) the post-Green Revolution period (after 1990), when first-generation modern varieties will be replaced by newer materials. Major benefits of the Nepalese wheat breeding program have included maintenance of disease resistance and faster dissemination of exotic germplasm. Attractive rates of return to investment in wheat breeding have been due in part to Nepal's ability to capture spillover benefits from neighboring countries and from international agricultural research centers.     

The Calculation of Returns to Research in Distorted Markets

Most of the empirical literature calculating rates of return to publicly sponsored research assumes that research is the only relevant government intervention. For most countries this assumption is untenable. This paper shows that improperly measuring government induced market distortions can severely bias research rate of return calculations. If the interaction between successful research and other government interventions increases the cost of the other interventions, then neglecting market distortions unambigously increases the calculated rate of return. Three examples of government induced distortions show that the magnitude of the upward bias in calculated rates of return can be extremely large - in some cases more than 100 percentage points. A normative implication is that governments should account for interactions between research and price interventions when determining research support levels. A positive implication is that existing government research funding patterns are more readily explainable as reasonable behavior by a government that accounts for these interactions.     

Patterns of Change in Child Labour and Schooling in Turkey: The Impact of Compulsory Schooling

Substantial improvements have taken place in the employment and schooling of children in Turkey. Decomposition analysis based on data from two time periods shows that a substantial part of the drop in child labour and over half of the increase in school enrolment can be attributed to the changing cost and benefit structures of work and schooling rather than to changing population characteristics. This paper establishes that work and schooling are incompatible activities and that the negative association between them has increased over time. The observed changes are attributed to the extension of compulsory schooling and the ban on child labour.     

The Sensitivity of Returns to Research Calculations to Supply Elasticity

Returns to research are thought to be robust under alternative supply elasticity assumptions. We show, both conceptually and numerically, how advances in approximating social benefits make returns to research sensitive to the supply elasticity. Despite this greater sensitivity, these advances retain conceptual and practical advantages. We make recommendations for dealing with the increased sensitivity.     

Economic Returns to Yield-increasing Research on Wheat in Western Canada

A multi-sector mathematical programming model of Canadian agriculture (CRAM) is employed to determine the rate of return to yield-increasing research on wheat conducted during 1962–91. The estimated internal rate of return to yield-increasing research ranged between 27% and 31% for the low wheat price scenarios. It was higher at 34–39% for the high wheat price scenarios. Producers captured 80–90% of the benefits. The results support the magnitude of estimated economic benefits reported in previous studies.     

Returns to smallholder dairying in the Kilimanjaro region,Tanzania

Tanzania is a net importer of dairy products despite its large cattle herd and successive government efforts to promote dairying. This paper draws on survey data to examine the financial attractiveness of dairying to smallholders in an area of high dairy potential on the slopes of Mount Kilimanjaro. On mixed farms in which coffee and bananas are the other main enterprises, producers keep small herds of mainly crossbred and grade cattle, mostly fed in stalls on cut forage and crop residues. Using a herd model, a benefit-cost analysis of dairying was carried out. This showed that at prevailing prices, returns to dairying were around 20%. There was, however, no difference in the returns gained by the larger scale farmers who had more of the grade cows and managed them intensively, compared to those using a less intensive system with lower potential stock. Moreover, the profitability of dairying for the former was underwritten by subsidies on inputs and fuel which are difficult to justify. Policy has apparently over-emphasised improving yields and the development of intensive dairying, and has not been sufficiently concerned with keeping down the costs of dairying.     

Nonparametric Estimation of Returns to Scale: Method and Application

The paper describes a method of estimating variable returns to scale in production that adaptively fits spline functions, using model selection criteria, to determine the appropriate number and location of break points for a fixed factor of production. Unlike other approaches, the method obtains nonparametric estimates of variable returns to scale for small samples while ensuring global curvature and flexibility properties are maintained. An application of the method is presented using data from the British Columbia sablefish fishery.
Les auteurs décrivent une méthode d'estimation des variations de rentabilité en fonction de l'échelle de production susceptibles de s'ajuster è des fonctions spline, utilisant des critéres modèles de sélection pour déterminer le nombre et la situation des seuils de rentabilité pour unfacteur de production fixe. À la différence d'autres avenues d'analyse, la méthode permet d'obtenir des valeurs non paramétriques de la rémunération variable selon l'échelle, è partir de petits échantillons, tout en garantissant le maintien de la courbure générale et de la souplesse d'application. Les auteurs proposent une application de la methode, utilisant les données des pêches de morue charbonnière en Colombie-Britannique.     

The Determination of Ex-Ante Returns

This study documents ex-ante returns to research in three areas of plant biotechnology-anther culture, protoplast and somatic hybridisation and recombinant D.N.A. techniques. The study uses Delphi forecasting methodology to estimate the potential contribution to increased yield expected to result from research in these emerging agricultural technologies. Returns to research were measured as internal rates of return and were found to vary from 15 percent to 40 percent.
Cette étude traite des rendements ex-ante de la recherche dans trois domaines de la biotechnologie des plantes—les techniques de la culture anthère, de l'hybridation somatique et protoplastique, et de la recombi-naison de l'A.D.N. L'étude utilise la méthodologie de previson Delphi pour estimer la contribution potentielle à l'accroissement des rendements anticipés de la recherche dans ces technologies agricoles nou-velles. Les rendements de la recherche étaient mesurés par les taux de rendement internes qui variaient de 15 percent à 40 percent.     

Accounting for Respondent Uncertainty to Improve Willingness-to-Pay Estimates

In this paper, we develop an econometric model of willingness to pay (WTP) that integrates data on respondent uncertainty regarding their own WTP. The integration is utility consistent, there is no recoding of variables, and no need to calibrate the contingent responses to actual payment data, so the approach can “stand alone.” In an application to a valuation study related to whooping crane restoration, we find that this model generates a statistically lower expected WTP than the standard contingent valuation (CV) model. Moreover, the WTP function estimated with this model is not statistically different from that estimated using actual payment data suggesting that, when properly analyzed using data on respondent uncertainty, CV decisions can simulate actual payment decisions. This method allows for more reliable estimates of WTP that incorporate respondent uncertainty without the need for collecting comparable actual payment data. Dans le présent article, nous avons élaboré un modèle économétrique d’estimation qui internalise l’incertitude des répondants quant à leur propre consentement à payer. L’internalisation est fidèle à la notion «d’utilité»; il n’a pas été nécessaire de transformer les variables ni de calibrer les réponses des répondants avec des paiements réels. L’application de la méthode n’est donc pas dépendante d’autres données ou méthodes. Dans une étude d’évaluation sur le rétablissement de la grue blanche d’Amérique dans laquelle ce modèle a été utilisé, nous avons trouvé que le consentement à payer attendu était statistiquement plus faible que celui obtenu à l’aide de la méthode d’évaluation contingente standard. Par ailleurs, la fonction de consentement à payer estimée à l’aide de ce modèle n’est pas statistiquement différente de celle estimée à l’aide de paiements réels. Cette observation autorise à penser que, lorsque le modèle tient compte des données sur l’incertitude des répondants, les décisions obtenues à l’aide de la méthode d’évaluation contingente peuvent simuler les décisions obtenues à l’aide de paiements réels. Cette méthode permet d’obtenir des estimations du consentement à payer plus fiables, lesquelles intègrent l’incertitude des répondants sans la nécessité de collecter des données comparables de paiements réels.     

Willingness-to-Pay Estimates and Their Relevance to Agribusiness Decision Making

Although methods such as contingent valuation have received a great deal of attention in environmental valuation literature, fewer studies have reported willingness-to-pay estimates with agribusiness applications. Because agribusinesses are increasingly interested in producing and selling differentiated goods and services whose values has not been established by well-functioning markets, we provide a short introduction to willingness-to-pay methodology and provide a discussion of several different methods used to estimate willingness-to-pay. More specifically, we discuss how much of the work in environmental and experimental valuation literature can be extended to agribusiness applications, which have their own set of unique issues.