poverty productivity and production environment a review of the evidence abstract this paper reviews the state of knowledge about the key issues needing to be understood to satisfactorily resolve a long standing debate within the consultative group for international agricultural research cgiar system the debate revolves around the effects on various populations particularly the poor of different allocations of research effort between marginal and favoured production environments this paper specifically focuses on what is known about the geographical distribution of the rural poor across agro ecological zones and over time variations in the income generating activities including non agricultural activities engaged in by the poor are examined and the ways in which specific technology packages affect the economic well being of different types of households both directly and indirectly

dynamic wage employment bargaining with employment adjustment costs this paper looks at the consequences of introducing employment adjustment costs into two standard models of trade unions the right to manage model and the efficient bargain model the authors look at how unions affect both the speed of adjustment to equilibrium and the long run equilibrium they examine the consequences of the model for the estimation of dynamic labor demand equations and for the testing of trade union models copyright 1989 by royal economic society

short run employment functions when the speed of adjustment depends on the unemployment rate a bstratacross industry and country comparisons have found the speed of adjustment in short run employment functions to be positively related to the rate of unemployment the present paper develops a time series model in which the reaction coefficient varies with unemployment and estimates it for the manufacturing sectors of the eight oecd countries for which suitable data are available the new model is non linear and is estimated using full information maximum likelihood procedures application of the log likelihood ratio test finds that the new vanable reaction coefficient model is superior to the fixed reaction coefficient model for the united states canada australia austria ireland and the united kingdom

the econometrics of damage control why specification matters the contribution of damage control agents to production differs fundamentally from that of standard inputs lands labor capital this paper develops an econometric model based on the key characteristics of damage control agents and examines its properties it demonstrates that standard production function specifications overestimate damage control agent productivity and have erroneous implications for the evolution of damage control agent productivity and use in response to changing environments e g the spread of pest resistance it also proposes several alternative specifications and discusses methods for estimating them

an economic analysis of soybean integrated pest management the type of pest management strategy a farmer chooses is influenced by the amount of risk associated with alternative strategies this paper examines the attractiveness of alternative pest management strategies used on a representative virginia soybean farm probability distributions of net revenue associated with alternative pest control options are simulated and then compared using generalized stochastic dominance criteria results suggest risk averse and in some cases risk preferring farmers would prefer strategies which incorporate an integrated pest management approach to pest control rather than one which relies completely on chemical pest control

redistribution of social benefits from advances in extension and research in the tanzanian maize industry abstract this study determined consumer and producer welfare gains from advances in extension and research in the maize industry of tanzania to determine how a national taxing schedule should be determined it was found that for an off farm marketable surplus of 40 consumers and producers gain equally while for an off farm marketable surplus of 60 consumers realize 75 of the welfare benefits this suggests that consumers and producers should share equally in a revenue generating tax for funding maize research and extension programs however for large producers with a marketable surplus of 60 or more their tax should decrease proportionally to the amount sold alternatively if taxed equally large scale producers should receive some form of compensation through direct government payments

labor adjustment costs in a destination country the case of mexico abstract rodrik rodrik d 1997 has globalization gone too far institute for international economics washington dc argues that firms use the threat of moving to low cost generally developing markets to make employment more flexible at home although a large literature documents significant adjustment costs in developed countries we know little about their size and importance in developing countries that receive capital we employ monthly mexican data from the gatt nafta period to estimate adjustment costs in mexico we consider adjustment costs for production and non production workers and allow for asymmetry while patterns of adjustment costs are similar as in developed countries adjustment costs in mexico are generally an order of magnitude smaller

technical change in senegal s irrigated rice sector impact assessment under uncertainty abstract this paper addresses the prospects for technical change in the irrigated rice sector of senegal and measures ex ante the economic returns to recent research efforts in 1994 three new rice varieties were released to farmers in the senegal river valley srv the major irrigated rice region in senegal the productivity advantage of the new varieties is based primarily on early maturity which permits double cropping the seeds are also higher yielding than existing cultivars we use a conventional akino and hayami 1975 am j agric econ 57 1 10 partial equilibrium model adapted to the senegalese situation to assess the social benefits of research and compare those to its costs in calculating the internal rate of return irr to account for uncertainty regarding the future values of model variables we use simulation which allows us to generate a distribution of all possible outcomes of the irr we find that rice research is almost certain to have a very high payoff over the 1995 2004 period the expected value of the irr is calculated to be 121 per year with a 97 5 probability that it lies above annual capital costs of 18

estimating the benefits of plant breeding research methodological issues and practical challenges impact assessment studies consistently show that the benefits generated by plant breeding are large positive and widely distributed numerous case studies have concluded that investment in plant breeding research generates attractive rates of return compared to alternative investment opportunities that welfare gains resulting from the adoption of modern varieties mvs reach both favoured and marginal environments and that benefits are broadly shared by producers and consumers but just how reliable are the results of studies that estimate the benefits of plant breeding research this article reviews methods used to estimate the benefits of plant breeding research and discusses theoretical and empirical issues that often receive inadequate attention in applied impact assessment work our objective is not to question the validity of the theoretical frameworks commonly used to estimate the benefits of plant breeding research but rather to examine problems that can arise when the widely accepted theoretical frameworks are used for empirical analysis most of these problems can be grouped into three basic categories 1 problems associated with measuring adoption and diffusion of mvs 2 problems associated with estimating benefits attributable to adoption of mvs and 3 problems associated with assigning credit among the various plant breeding programmes that participated in developing the mvs

unemployment in britain male unemployment in britain has risen from around 2 per cent in the 1950s to around 17 per cent in 1985 see figure 1 the figures are for male unemployment because there is no consistent series for women 1 even more remarkably unemployment has fallen in only three years out of the last twenty 1973 1978 and 1979 to account for this we need a model that explains both changes in the natural or non accelerating inflation rate of unemployment nairu and deviations from it we use a three equation supply side model centred on the labour market this has two main features the first concerns the determination of employment in the short run the labour demand function that we use cuts through the fruitless debate now raging especially in europe as to whether current unemployment is classical or keynesian according to the classical view employment is too high because real wages are too high according to the keynesian view real wages are not binding and unemployment is high because the product market does not clear with prices too high relative to nominal demand the whole debate is set in the framework of perfect competition yet in perfect competition prices are set by impersonal forces and it is not clear what could possibly stop prices clearing the market it is much more reasonable to think of prices as being set by imperfectly competitive firms existing prices being the best they can think of given the demand they face in this context firms demand for labour will depend on both the real product wage and the level of real aggregate demand this is the demand function we estimate and it conforms both to common sense and to the data however this does not imply that employment can be made to grow without limit by pumping up real demand for in the medium term when price surprises are eliminated our model determines three variables employment real wages and real demand on the basis of three equations an employment equation a price equation and a wage equation thus in the medium term there is a natural level of employment and corresponding to this a natural level of real aggregate demand the second key feature of our model concerns the medium term determination of unemployment in the medium term the planned mark up of wages over prices in wage settlements must be consistent with the mark up of prices over wage costs in employers pricing behaviour for if wage setters try to set real product wages higher than is consistent with employers pricing behaviour this generates ever increasing inflation thus the key to understanding unemployment in the medium term is the behaviour of wage setters if events occur that push them towards too high real wages then unemployment has to rise to offset these influences we shall call these influences wage pressure variables or push factors and they are clearly crucial in understanding unemployment the variables here include the social security system employment protection

impacts of food crop improvement research evidence from sub saharan africa abstract the paper reviews and summarizes evidences of impacts of crop improvement research of major food crops in africa it provides evidence of increased availability of improved varieties of major food crops to farmers in africa increased food production in regions where adoption has occurred and positive returns to research investment indicating that agricultural research in africa has had productivity increasing impacts on its agriculture however research impacts vary considerably across countries and regions within a country as a result of agroclimatic factors and policy environment which affects the supply of seeds and other inputs and the continuity and stability of research investments the paper points to a number of important issues both internal and external to the agricultural research system organization that need to be addressed if agricultural research is to provide a stimulus for modernizing african agriculture given the small size of food crop production area in many african countries it is important for research systems to take full advantage of research spill ins from regional and international research organizations there is a great potential to increase the efficiency of research systems by improving the coordination among members of national research systems and continuing improvements in collaborations between narss and regional and international organizations

employment in the british coal industry a test of the labour demand model the authors test the conventional model of labor demand against the alternative that bargaining takes place over both wages and employme nt for a time series cross section data set covering the british coal industry they note the difficulty of identifying the contract curve under the alternative hypothesis and suggest the use of variables affecting the union and management status quo points as instruments for the endogenous wage they find that outside variables such as benefits and manufacturing wages are important in determining the level of employment thus rejecting the labor demand model copyright 1988 by royal economic society

economic returns to crop management research in a post green revolution setting returns to research studies have neglected research on crop management cmr which may account for half of all crop research because cmr enhances the efficiency of input use returns to cmr are hypothesized to increase in settings characterized by high input levels and high yields a method is developed to estimate returns to cmr and this method is applied to wheat research in a post green revolution setting in northwest mexico the results suggest that returns to cmr are positive over a range of model assumptions

modernization of a peasant crop in colombia evidence and implications abstract the survival of the small farm sector in the process of agricultural modernization in latin america has been a concern for many authors and institutions it is generally believed that the small farm sector is bypassed in the process of agricultural development the authors analyze modernization of bean maize cropping systems in southern colombia prices production practices and profitability are compared for 1975 and 1989 by means of a production function the effects of allocative efficiency technical efficiency and technical change on productivity and profitability are analyzed the observed changes reflect very well the price trends over the period between 1975 and 1989 total factor productivity increased by 50 bean maize producers almost doubled returns to land and labor increased technical efficiency had most effect on profitability followed by technical change allocative efficiency had more impact on yields than on profitability because it was associated with high input costs considerable opportunities for further productivity increases were identified conclusions on the nature of the modernization process are drawn implications for agricultural policy research and the role of the small farm in agricultural development are derived

intertemporal rules with variable speed of adjustment an application to u k manufacturing employment this paper presents a procedure to estimate intertemporal dynamic decision rules where adjustment costs are assumed to be variable the estimation is based on the euler equation for purposes of illustration the authors concentrate on an employment function for the u k manufacturing sector where they find very significant effects of some variables that influence adjustment costs finally they point out an empirical result that has interesting implications when evaluating tests of efficient bargain models copyright 1989 by royal economic society

employment adjustment in uk manufacturing this analysis differs from previous studies of labor demand in its explicit inclusion of the costs to the firm of adju sting its workforce these costs include institutional factors such a s employment protection legislation and unions and market factors su ch as the degree of slack in the labor market two questions are addr essed what is the quantitative impact of these forces and does their inclusion improve the fit of a labor demand function the results sh owed these factors to have a strong influence on the rate of hiring f iring and to improve significantly on conventional labor demand funct ions copyright 1988 by royal economic society

mobility costs frictional unemployment and efficiency with imperfect job information flows it is plausible that the distribution of job offerings becomes more attractive when there are more vacancies and more unemployed with word of mouth communication this condition is derived given this condition steady state equilibrium is not efficient with welfare increased by the introduction of unemployment compensation even though all agents are risk neutral in this way workers become more selective in the jobs they accept

the politics of infrastructure investment the role of product market competition abstract in spatial competition public infrastructure plays a crucial role in determining product market outcomes in our model consideration of infrastructure s impact on the product market drives the preferences of consumers in their dual role as voter taxpayers the spatial heterogeneity of consumers produces conflicting political interests and in many cases inefficient outcomes however across both exogenous and endogenous market environments product market competition consistently leads to higher levels of publicly funded infrastructure than monopoly collusion furthermore competition s boost to the popular support for infrastructure investment is often excessive while monopoly leads to underinvestment

the economics of wheat research in developing countries the one hundred million dollar puzzle abstract currently 1 150 scientists are carrying out wheat improvement research in developing countries with an annual budget of around 100 million because of the recent reduction in agricultural research budgets this study marshalls evidence from 71 wheat research programs in 35 developing countries to address the following puzzle what is the optimal size type and location of wheat research programs in the developing world the analysis reveals that if research spillins are taken into consideration almost half of the wheat improvement programs in developing countries are inefficient the efficiency of wheat research in many national agricultural research systems can be increased by reducing the size of research programs consolidating state and federal research programs and shifting from wheat breeding research to capturing spillins from other countries and from the international maize and wheat improvement center cimmyt