learning about a new technology pineapple in ghana this paper investigates the role of social learning in the diffusion of a new agri cultural technology in ghana we use unique data on farmers communication patterns to define each individual s information neighborhood conditional on many potentially confounding variables we find evidence that farmers adjust their inputs to align with those of their information neighbors who were surpris ingly successful in previous periods the relationship of these input adjustments to experience further indicates the presence of social learning in addition applying the same method to input choices for another crop of known technol ogy correctly indicates an absence of social learning effects jel d83 013 033 q16

household level determinants of adoption of improved natural resources management practices among smallholder farmers in western kenya abstract integrated natural resources management inrm of which integrated soil fertility management isfm is a component offers considerable promise for increasing food production in kenya it nonetheless remains unclear whether isfm inrm techniques lend themselves easily to adoption by smallholder farmers using panel data collected in western kenya in 1989 and 2002 this study finds that resource constraints limit many farmers adoption of isfm inrm techniques the size of the farm owned by a household the value of its livestock off farm income family labor supply and the educational attainment and gender of the household head all had a significant positive effect on the likelihood of adoption similar factors were found to be statistically significant in discouraging abandonment of the practices under study there thus seem to exist reinforcing feedback between investments in soil fertility management and household wealth as measured by asset endowments our findings raise important questions as to whether isfm and related techniques are really affordable to poorer smallholder farmers

land clearance and social capital in mountain agro ecosystems the case of opuntia scrubland in ayacucho peru abstract opuntia scrublands are important ecological economic systems in rural andean areas they provide goods for peasants diet and animal feed as well as cochineal insects a highly valued source of dyes land clearance on these scrublands promotes changes in land use from nonproductive wilderness to cochineal and fruit harvest areas grazing lands and fuel wood supply zones here we empirically explore the role of social capital on land clearance based on a case study of the humanga region of ayacucho peru the literature on social capital is showing evidence of the positive effect of social capital on development actions and on environmental conservation in rural areas of developing countries such as participatory forest management here the notion of social capital is captured by the idea that some features of social organization such as networks facilitate coordination and cooperation within the peasant communities that help in managing different economic activities both on and off farm the habilitation of the scrublands in the andean mountain environment could be generating negative externalities as a consequence of altering the vegetation cover such as soil erosion because the benefits arising from land clearance activities are obtained by cochineal collecting households and the negative environmental effects are costs imposed upon noncochineal collectors the social capital associated with scrubland habilitation could be perverse from an agro environmental viewpoint and a revision of some government policies and of some ngos actions for rural development through the promotion of various community networks in this deprived area could be needed

supply chain design and adoption of indivisible technology in this paper we develop a framework to analyze adoption of indivisible technologies by relatively small farms using a threshold diffusion model it shows that different supply chains may emerge to enable the adoption of indivisible technologies independent technology dealers may buy the indivisible equipment and rent it to farmers when the gain from adoption is not affected by scale or ownership of the technology also larger farmers may buy the technology equipment and rent it renting the machine per se or providing a set of services that includes use of the machinery for the farmer buying the service to smaller farmers especially when there are gains from scale or ownership the paper derives equilibrium prices and quantities in the output equipment and technology rental market these equilibrium prices and quantities depend on the heterogeneity of farmers and the features of the technology introduction of the new indivisible technology will benefit larger adopting farmers and consumers but may hurt non adopters we illustrate our conceptual findings with empirical examples

the effects of improved roads on wages and employment evidence from rural labour markets in indonesia abstractthis paper examines the impact of road quality on labour supply and wages using household panel data from rural indonesia the analysis uses fixed effect instrumental variable estimation by first differencing two round panel data first road projects are found to increase the transportation speed second the empirical results from intra village variations of household endowments and labour market behaviour show that an increase in transportation speed raised wages in both non agricultural and agricultural employment and was associated with a decline in working time in agricultural employment for the households whose members are relatively educated the findings support potential complementarity between road quality and education implying that the government s public investments in roads and education should be coordinated to capture cross augmenting positive impacts in the long run

decomposing learning by doing in new plants the paper examines learning by doing in the context of a production function in which the other arguments are labor human capital physical capital and vintage as a proxy for embodied technical c

land use change with spatially explicit data a dynamic approach most of the economic literature that uses spatially explicit data to estimate the determinants of land use change is limited to static models and cross sectional data sets recent attempts to move to a more dynamic analysis include using panel data sets and survival analysis in this study we use a discrete choice dynamic model of land use where the agent s choices are regarded as the solution to a dynamic optimization problem the irreversibility of some decisions expectations about future prices and forward looking behavior of the land operator can all be accounted for our results show that a model specification that incorporates some of the complexities of the decision process improves upon results found in the existing literature first prediction accuracy of land use change is superior to any of the existing models second we demonstrate that models that do not account for transactions costs tend to overestimate the effects of changes in transportation costs

can a well fitted equilibrium asset pricing model produce mean reversion in recent papers cecchetti et al 1990 and kandel and stambaugh 1990 showed that negative serial correlation in long horizon returns was consistent with an equilibrium model of asset pricing in this paper we show that their results rely on misspecified markov switching models for the endowment process once the proper markov specification is chosen for the endowment process the model does not produce mean reversion of the magnitude detected in the data furthermore the small amount of mean reversion produced by the model is due only to small sample bias we also show that this model is unable to predict negative excess returns contrary to empirical evidence

are nonconvexities important for understanding growth everyday experience and a simple logical argument show that nonconvexities are essential for understanding growth compared to previous statements of this well known argument the presentation here places more emphasis on the distinction between two of the fundamental attributes of any economic good rivalry and excludability it also emphasizes the difference between public goods and the technological advances that are fundamental to economic growth like public goods technological advances are rionrival goods hence they are inextricably linked to nonconvexities but in contrast to public goods which are nonexcludable technological advances generate benefits that are at least partially excludable hence innovations in the technology are for the most part privately provided this means that nonconvexities are relevant for goods that trade in private markets consequently an equilibrium with price taking in all markets cannot be sustained concluding remarks describe some of the recent equilibrium growth models that do not rely on price taking and highlight some of the implications of these models this abstract was borrowed from another version of this item

adoption of agricultural innovations in developing countries a survey this paper reviews various studies which have provided a description and possible explanation to patterns of innovation adoption in the agricultural sector the survey points out that the tendency of many studies to consider innovation adoption in dichotomous terms adoption nonadoption may not be appropriate in many cases where the actual decisions are defined over a more continuous range more attention needs to be given to the socio cultural and institutional environment in area studies so that their interrelation with economic factors affecting adoption can be inferred the presence of several interrelated innovations is another aspect that needs to be considered more carefully in future research since a number of simultaneous decisions may be involved furthermore the possibility of regular sequential patterns in adopting components of a new technological package should be specifically addressed in future studies finally the impact of differential adoption rates on land holding distribution merits attention in future research

the aggregation of environmental benefit values welfare measures distance decay and total wtp abstract we review the literature regarding the aggregation of benefit value estimates for non market goods two case studies are presented through which we develop an approach to aggregation which applies the spatial analytic capabilities of a geographical information system to combine geo referenced physical census and survey data to estimate a spatially sensitive valuation function these case studies show that the common reliance upon political rather than economic jurisdictions and the use of sample mean values within the aggregation process are liable to lead to significant errors in resultant values we also highlight the fact that for resources with use values then we should expect overall values to reduce with increasing distance from such sites but that changes in the choice of welfare measure will determine whether such distance decay is to be expected within values stated by those who are presently non users the paper concludes by providing recommendations for future improvements to the methodology

a continuous logit hotelling model with endogenous locations of consumers this paper analyzes location and price choices of firms and subsequent location choices of consumers in a linear city model when consumers have different perceptions of locations and firms the study utilizes a continuous logit model to describe consumers location and supplier choices a unique subgame perfect nash equilibrium exists where firms make positive profits and the minimum differentiation principle applies for identical firms prices converge to marginal costs as heterogeneity of consumers perceptions disappears

equilibrium existence in the linear model of spatial competition this paper considers a generalization of the hotelling model of spatial competition it is shown that a pure strategy perfect equilibrium in the two stage location price game exists only under very stringent conditions these conditions are in fact the conditions for profit to be concave in price for any given location pair when the solution concept is extended to allow for mixed strategies there is no symmetric equilibrium involving pure strategies if transport costs are not sufficiently convex the convexity of transport costs is crucial in determining whether there is excessive or insufficient diversity of products copyright 1988 by the london school of economics and political science

the principle of minimum differentiation revisited abstract hotelling s model of differentiated products is examined and modified so that consumers have relatively low reservation prices for the differentiated products the problem of existence of a nash equilibrium in prices in a duopoly with given products is analysed when the reservation price is relatively low a nash equilibrium in prices exists for a larger range of products than when the reservation price is infinite next i examine product competition with instantaneous adjustment to the nash equilibrium prices of the previous game firms competing in a nash fashion have tendencies to move away from each other and try to achieve local monopolistic positions this is in sharp contrast with the acclaimed principle of minimum differentiation of the original model of hotelling of high reservation price where firms clustered in the product space

learning by doing and learning from others human capital and technical change in agriculture household level panel data from a nationally representative sample of rural indian households describing the adoption and profitability of high yielding seed varieties hyvs associated with the green revolution are used to test the implications of a model incorporating learning by doing and learning spillovers the estimates indicate that i imperfect knowledge about the management of the new seeds was a significant barrier to adoption ii this barrier diminished as farmer experience with the new technologies increased iii own experience and neighbors experience with hyvs significantly increased hyv profitability and iv farmers do not fully incorporate the village returns to learning in making adoption decisions

modeling technology adoption in developing countries an analysis of technology adoption decisions by poor farmers is provided some possible empirical models for studying technology adoption are reviewed the issue of theoretical consistency is dealt with in terms of the costs of such consistency measured in data needs and model complexity and the benefits measured in terms of understanding the micro economic foundations of adoption

temporal and spatial modelling of tropical deforestation a survival analysis linking satellite and household survey data we estimate a spatially explicit model of the forest clearance process among smallholder farmers in an agricultural frontier of southern mexico our analysis takes as its point of departure a simple utility maximising model that suggests many possible determinants of deforestation in an economic environment characterised by missing or thin markets hypotheses from the model are tested on a data set that combines a time series of satellite imagery with data collected from a survey of farm households whose agricultural plots were geo referenced using a global positioning system gps we implement a survival analysis to identify the effect of household level explanatory variables on the probability of deforestation this approach allows us to introduce a measure of the time until clearance as a covariate thereby affording a control for the effect of potentially important explanatory variables that vary through time but are not directly observable in addition to identifying several variables relevant for policy analysis including household demographics proximity to roads and government provision of agricultural support model results suggest that the deforestation process is characterised by non linear duration dependence with the probability of forest clearance first decreasing and then increasing with the passage of time

property rights and deforestation in the brazilian amazon this paper focuses on the impact of property rights insecurity on deforestation in the brazilian legal amazon deforestation is considered as a risk management strategy property rights insecurity reduces the present value of forests and fosters forest conversion into agricultural and pasture lands moreover deforestation is the consequence of strategic interactions between landowners and squatters landowners clear the forest preventively in order to assert the productive use of land and to reduce the expropriation risk squatters invade land plots clear the forest and may afterwards gain official recognition with formal property titles a particular attention is paid to the measure of land property rights insecurity in the brazilian context it is assumed that property rights insecurity has a multidimensional character taken into account by the number of homicides related to land conflicts and expropriation procedures principal component analysis allows synthesising such information an econometric model of deforestation is estimated on a panel dataset on the 1988 2000 period and the nine states of the brazilian legal amazon the hypothesis that insecure land property rights contribute to higher rates of deforestation is not rejected when the simultaneity bias between insecure property rights and deforestation is addressed this result questions the modality of the brazilian land reform that considers forested areas as unproductive and thus open for expropriation procedures

spatial externalities in agriculture empirical analysis statistical identification and policy implications summary spatial externalities can affect economic welfare and landscape pattern by linking farm returns on adjoining parcels of land while policy can be informed by research that documents spatial externalities statistically quantifying the presence of externalities from landscape pattern is insufficient for policy guidance unless the underlying cause of the externality can be identified as positive or negative this article provides a springboard for empirical research by examining the underlying structure social environmental interactions and statistical identification strategies for the analysis and the quantification of agricultural spatial externalities that are derived from observations of landscape change the potential for original policy treatments of agricultural spatial externalities in development and environment outcomes is highlighted

social influence and collective action effects on farm level soil conservation effort in rural kenya abstract this paper analyzes the effects of social influence and participation in collective action initiatives on soil conservation effort among smallholder farmers in lake naivasha basin kenya we apply binary and ordered probit models in a two stage regression procedure to cross sectional data collected through a household survey among randomly selected smallholder farmers smallholder farming systems in the research area are associated with practices that render farmlands susceptible to soil erosion causing negative impacts on land and the environment therefore strategies that encourage soil conservation are likely to also offer solutions for dealing with agri environmental challenges and poverty alleviation results indicate that social capital facilitates participation in collective action initiatives which then influence individual soil conservation efforts neighborhood social influences subjective norms gender education level farm size access to credit and livestock ownership also emerge as key determinants of soil conservation effort policy implications drawn by this study encourage strategies to increase participation and effectiveness in collective action initiatives as a boost to soil conservation implementation of soil conservation practices could also be encouraged through awareness increasing instruments facilitating access to agricultural micro credit and paying attention to gender related challenges on knowledge access and rights over land and other natural resources

capturing household level spatial influence in agricultural management using random effects regression abstract data on agricultural and natural resource management typically have spatial patterns related to the landscapes from which they came consequently econometric models designed to explain the determinants of humans natural resource management practices or their outcomes often have spatial structure that can bring bias or inefficiency to parameter estimates although econometric tools are available to correct for spatial structure such tools are largely lacking for use with discrete dependent variable models while one obvious solution would be to develop the necessary tools an alternative is to identify conditions under which spatial dependency can be managed effectively without formal spatial autoregressive models this study examines conditions under which spatial structure corresponds closely to defined agro ecological zones making it possible to model spatial effects by random effects regression using household survey data sampled along agro ecological zone strata this article develops two models of links between farmer assets and agricultural natural resource degradation in southern peru the first stage model looks at determinants of crop yield loss over time an index of soil productivity while the second stage model looks at determinants of the extent of fallow cycles in crop rotation a key agricultural practice reducing crop yield loss diagnostic statistics for spatial dependency reveal spatial structure particularly in the fallow model this spatial dependency is eliminated in the ordinary least squares ols models by inclusion of the agro ecological zone random effects in the spatially dependent fallow model comparison of coefficient estimates between ols and the spatial autoregressive maximum likelihood models showed ols with random effects to give virtually identical results to the spatial autoregressive models making the latter unnecessary these results show that spatial structure in natural resource management models can sometimes be captured by zonal variables when this occurs random effects regression can largely eliminate spatial dependency a necessary precondition for this approach with household survey data is prior sample stratification according to landscape characteristics where random effects models can effectively capture spatial structure they may also offer analysts greater flexibility in analyzing models with limited dependent variables

does twitter chatter matter online reviews and box office revenues with a rapid rise of text based social media and online word of mouth wom activity millions of people express their thoughts and opinions on a variety of topics considering that nowadays wom is

dynamics of variety change on wheat farms in pakistan a duration analysis abstract decades after the green revolution sustaining wheat productivity remains an important policy goal for the government of pakistan understanding the speed of diffusion of new wheat varieties can contribute to this goal we apply duration analysis to identify the factors that shorten the time until a farmer replaces one modern variety by another and test hypotheses concerning two recurring themes of the green revolution farm size differences and the role of information sources in seed diffusion we find that time to adoption averages only 4 years but is shorter on larger farms factors that speed variety change also differ by farm size extension and media sources of information significantly influence adoption among larger farmers relative to information gained through social relationships but this is not the case for marginal farmers traits related to consumption quality speed adoption on smaller wheat farms where families both sell and consume their wheat higher yields drive adoption for the most subsistence oriented marginal group

o ring production on u s hog farms joint choices of farm size technology and compensation we hypothesize that hog production can be characterized by complementarities between new technologies worker skills and farms size such production processes are consistent with kremer s 1993 o ring production theory in which a single mistake in any one of several complementary tasks in a firm s production process can lead to catastrophic failure of the product s value in hog production mistakes that introduce disease or pathogens into the production facility can cause a total loss of the herd consistent with predictions derived from the o ring theory we provide evidence that the most skilled workers concentrate in the largest and most technologically advanced farms and are paid more than comparable workers on smaller farms these findings suggest that worker skills new technologies and farm size are complements in production the complementarities create returns to scale to large hog confinements consistent with the dramatic increase in market share of very large farms over the past 20 years

learning regime switches and equilibrium asset pricing dynamics abstract we examine the autocorrelation properties of equilibrium returns when the growth rate of dividends consumption or gnp follows a markov switching process in contrast to earlier studies we assume that the agent learns the current growth state using observed dividends and bayes rule for the model with switching in the mean growth rate we find that learning significantly alters the pattern of returns often generating positive rather than negative autocorrelation for the model calibrated to gnp with switching in the variance of the growth rate we show that learning induces negative autocorrelation

seeing is believing evidence from an extension network experiment extension is designed to enable lab to farm technology diffusion decentralized models assume that information flows from researchers to extension workers and from extension agents to contact farmers cfs cfs should then train other farmers in their communities such a modality may fail to address informational inefficiencies and accountability issues the authors run a field experiment to measure the impact of augmenting the cf model with a direct cf training on the diffusion of a new technology all villages have cfs and access the same extension network in treatment villages cfs additionally receive a three day central training on the new technology they track information transmission through two nodes of the extension network from extension agents to cfs and from cfs to other farmers directly training cfs leads to a large statistically significant increase in adoption among cfs however higher levels of cf adoption have limited impact on the behavior of other farmers

the role of information and social interactions in retirement plan decisions evidence from a randomized experiment this paper analyzes a randomized experiment to shed light on the role of information and social interactions in employees decisions to enroll in a tax deferred account tda retirement plan within a large university the experiment encouraged a random sample of employees in a subset of departments to attend a benee ts information fair organized by the university by promising a monetary reward for attendance the experiment multiplied by more than e ve the attendance rate of these treated individuals relative to controls and tripled that of untreated individuals within departments where some individuals were treated tda enrollment e ve and eleven months after the fair was signie cantly higher in departments where some individuals were treated than in departments where nobody was treated however the effect on tda enrollment is almost as large for individuals in treated departments who did not receive the encouragement as for those who did we provide three interpretations differential treatment effects social network effects and motivational reward effects to account for these results

participation and investment decisions in a retirement plan the influence of colleagues choices abstract this paper investigates whether peer effects play an important role in retirement savings decisions we use individual data from employees of a large university to study whether individual decisions to enroll in a tax deferred account plan sponsored by the university and the choice of the mutual fund vendor for people who choose to enroll are affected by the decisions of other employees in the same department to overcome the identification problems we divide the departments into sub groups along gender status age and tenure lines and we instrument the average participation of each peer group by the salary or tenure structure in this group our results suggest that peer effects may be an important determinant of savings decisions

bayesian learning in social networks we study the perfect bayesian equilibrium of a sequential learning model over a general social network each individual receives a signal about the underlying state of the world observes the past actions of a stochastically generated neighbourhood of individuals and chooses one of two possible actions the stochastic process generating the neighbourhoods defines the network topology we characterize pure strategy equilibria for arbitrary stochastic and deterministic social networks and characterize the conditions under which there will be asymptotic learning convergence in probability to the right action as the social network becomes large we show that when private beliefs are unbounded meaning that the implied likelihood ratios are unbounded there will be asymptotic learning as long as there is some minimal amount of expansion in observations we also characterize conditions under which there will be asymptotic learning when private beliefs are bounded

introduction to the special issue on spatial analysis for agricultural economists abstract the goal of this special issue is to introduce agricultural economists to new analytical approaches involving spatial data this paper provides a brief history of the special issue and an introduction to von thunen s model of the determinants of land use and rent that underlies all spatial analysis

time to change what to sow risk preferences and technology adoption decisions of cotton farmers in china this paper examines the role of individual risk attitudes in the decision to adopt a new form of agricultural biotechnology in china i conducted a survey and a field experiment to elicit the risk preferences of chinese farmers who faced the decision of whether to adopt genetically modified bt cotton a decade ago in my analysis i expand the measurement of risk preferences beyond expected utility theory to incorporate prospect theory i find that farmers who are more risk averse or more loss averse adopt bt cotton later farmers who overweight small probabilities adopt bt cotton earlier

deforestation land use and property rights empirical evidence from darien panama economic conventional wisdom suggests that providing land users with more secure property rights will result in more sustainable land use and less deforestation in this paper we use spatial econometric techniques to evaluate quantitatively the effect on land use of designated property rights in three parts of darie n province a national park where no human activity is supposed to occur and two reserves for indigenous peoples results suggest that legal property rights for an indigenous population can influence land use geography appears to be more important than legal protection for the national park

mean reversion in equilibrium asset prices this paper demonstrates that negative serial correlation in long horizon stock returns is consistent with an equilibrium model of asset pricing when investors display only a moderate desire to smooth their consumption commonly used measures of mean reversion in stock prices calculated from historical returns data nearly always lie within a 60 percent confidence interval of the median of the monte carlo distributions implied by the authors equilibrium model from this evidence the authors conclude that the degree of serial correlation in the data could plausibly have been generated by their model copyright 1990 by american economic association

the role of tenure security and private time preference in neotropical deforestation a survey of 209 chimane amerindian households in 18 villages in the bolivian rain forest was done to examine the role of tenure security and private time preference on the clearance of old growth forest results of tobit regressions suggest that conflict with abutters was associated with more deforestation but the average impatience of the household heads was associated with less deforestation results suggest that governments should protect the land rights of indigenous people if they wish to enhance conservation results cast doubts on the idea that high private time preference increases the depletion of natural resources