a generalized schwartz model for energy spot prices estimation using a particle mcmc method we propose an energy spot price model featuring a two factor price process and a two component stochastic volatility process the first factor in the price process captures the normal variations the second accounts for spikes the two component volatility allows for a flexible autocorrelation structure instead of using various filtering techniques for splitting the two factors as often found in the literature we estimate the model in one step using an adaptive mcmc method with a rao blackwellized particle filter we fit the model to uk natural gas spot prices and investigate the importance of spikes and stochastic volatility we find that the inclusion of stochastic volatility is crucial and that it strongly impacts the jump intensity in the spike process furthermore our estimation method enables us to consider both continuous and purely jump driven volatility processes and thereby assess if the volatility specification also influences the spike process and the overall model fit

market fundamentals competition and natural gas prices after the liberalisation of the gas industry trading hubs have emerged in europe although these hubs appear to be liquid market places fostering gas to gas competition the efficiency of the gas market remains a topic of interest as a fair share of gas is still traded through long term contracts with prices linked to the oil price while the number of gas suppliers to the european market is limited in order to assess the efficiency of the gas market we analyse the day ahead spot price at the dutch gas hub over the period 2011 2014 we find that the oil price had a small positive impact on the gas price changes in the concentration on the supply side did not affect the movement in gas prices the availability of gas in storages and the outside temperature negatively influenced the gas price we also find that the gas price was related to the production of wind electricity overall we conclude that the day ahead gas prices are predominantly determined by gas market fundamentals policies to further integrate gas markets within europe may extend this gas to gas competition to a larger region

liquidity risk and occupational choices we explore which financial constraints matter the most in the choice of becoming an entrepreneur we consider a randomly assigned welfare program in rural mexico and show that cash transfers signi cantly increase entry into entrepreneurship we then exploit the cross household variation in the timing of these transfers and find that current occupational choices are significantly more responsive to the transfers expected for the future than to those currently received guided by a simple occupational choice model we argue that the program has promoted entrepreneurship by enhancing the willingness to bear risk as opposed to simply relaxing current liquidity constraints

stochastic modeling of financial electricity contracts abstract we discuss the modeling of electricity contracts traded in many deregulated power markets these forward futures type contracts deliver either physically or financially electricity over a specified time period and is frequently referred to as swaps since they in effect represent an exchange of fixed for floating electricity price we propose to use the heath jarrow morton approach to model swap prices since the notion of a spot price is not easily defined in these markets for general stochastic dynamical models we connect the spot price the instantaneous delivery forward price and the swap price and analyze two different ways to apply the heath jarrow morton approach to swap pricing either one specifies a dynamics for the non existing instantaneous delivery forwards and derives the implied swap dynamics or one models directly on the swaps the former is shown to lead to quite complicated stochastic models for the swap price even when the forward dynamics is simple the latter has some theoretical problems due to a no arbitrage condition that has to be satisfied for swaps with overlapping delivery periods to overcome this problem a practical modeling approach is analyzed the market is supposed only to consist of non overlapping swaps and these are modelled directly a thorough empirical study is performed using data collected from nord pool our investigations demonstrate that it is possible to state reasonable models for the swap price dynamics which is analytically tractable for risk management and option pricing purposes however this is an area of further research

long run effects of public sector sponsored training in west germany between 1991 and 1997 west germany spent on average about 3 6 bn euro per year on public sector sponsored training programmes for the unemployed we base our empirical analysis on a new administrative data base that plausibly allows for selectivity correction by microeconometric matching methods we identify the effects of different types of training programmes over a horizon of more than seven years using bias corrected weighted multiple neighbours matching we find that all programmes have negative effects in the short run and positive effects over a horizon of about four years however for substantive training programmes with duration of about two years gains in employment probabilities of more than 10 points appear to be sustainable but come at the price of large negative lock in effects

are poor people credit constrained or myopic evidence from a south african panel credit constraints are an almost ubiquitous assumption in development economics yet direct evidence for credit constraints is limited and many observations consistent with credit constraints are equally compatible with myopic non forward looking consumption or precautionary saving using household panel data and a source of widely anticipated income in south africa this paper tests and rejects the standard consumption model with perfect capital markets then myopic consumption and precautionary saving are tested as alternative explanations for the observed jumps in expenditure the standard model with credit constraints cannot be rejected in favour of myopic consumption or precautionary saving

delegated portfolio management abstract a problem of screening agents with privately known forecasting abilities and reservation utilities and then eliciting truthful information from these agents once they are employed is considered for the case of risk averse agents and large principals an approximately optimal solution is constructively characterized under the assumption that payoffs are normally distributed a significant extension of the definnetti savage probability elicitation result is developed under this extension knowledge of agent preferences is not required when the underlying conditional distributions are symmetric and this fact is exploited to solve the screening problem in a mean variance formulation

health shocks and risk aversion we empirically assess whether a health shock influences individual risk aversion we use grip strength data to obtain an objective health shock indicator in order to account for the non random nature of our data regression adjusted matching is employed risk preferences are traditionally assumed to be constant however we find that a health shock increases individual risk aversion the finding is robust to a series of sensitivity analyses and persists for at least four years after the shock income changes do not seem to be the driving mechanism

stochastic convenience yield and the pricing of oil contingent claims this paper develops and empirically tests a two factor model for pricing financial and real assets contingent on the price of oil the factors are the spot price of oil and the instantaneous convenience yield the parameters of the model are estimated using weekly oil futures contract prices from january 1984 to november 1988 and the model s performance is assessed out of sample by valuing futures contracts over the period november 1988 to may 1989 finally the model is applied to determine the present values of one barrel of oil deliverable in one to ten years time

moral hazard and the portfolio management problem this paper investigates the significance of nonlinear contracts on the incentive for portfolio managers to collect information in addition the manager must be motivated to disclose this information truthfully we analyze three contracting regimes 1 first best where effort is observable 2 linear with unobservable effort and 3 the optimal contract within the bhattacharya pfleiderer quadratic class we find that the linear contract leads to a serious lack of effort expenditure by the manager this underinvestment problem can be successfully overcome through the use of quadratic contracts these contracts are shown to be asymptotically optimal for very risk tolerant principals

electricity derivatives pricing with forward looking information in order to increase overall transparency on key operational information power transmission system operators publish an increasing amount of fundamental data including forecasts of electricity demand and available capacity we employ a fundamental model for electricity prices which lends itself well to integrating such forecasts while retaining ease of implementation and tractability to allow for analytic derivatives pricing formulae in an extensive futures pricing study the pricing performance of our model is shown to further improve based on the inclusion of electricity demand and capacity forecasts thus confirming the general importance of forward looking information for electricity derivatives pricing however we also find that the usefulness of integrating forecast data into the pricing approach is primarily limited to those periods during which electricity prices are highly sensitive to demand or available capacity whereas the impact is less visible when fuel prices are the primary underlying driver to prices instead

agricultural household models extensions applications and policy this book presents the basic model of an agricultural household that underlies most of the case studies undertaken so far the model assumes that households are price takers and is therefore recursive the decisions modeled include those affecting production and the demand for inputs and those affecting consumption and the supply of labor comparative results on selected elasticities are presented for a number of economies the empirical significance of the approach is demonstrated in a comparison of models that treat production and consumption decisions separately and those in which the decisionmaking process is recursive the book summarizes the implications of agricultural pricing policy for the welfare of farm households marketed surplus the demand for nonagricultural goods and services the rural labor market budget revenues and foreign exchange earnings in addition it is shown that the basic model can be extended in order to explore the effects of government policy on crop composition nutritional status health saving and investment and to provide a more comprehensive analysis of the effects on budget revenues and foreign exchange earnings methodological topics primarily the data requirements of the basic model and its extensions along with aggregation market interaction uncertainty and market imperfections are discussed the most important methodological issues the question of the recursive property of these models is also discussed

valuation of commodity based swing options in the energy markets in particular the electricity and natural gas markets many contracts incorporate flexibility of delivery options known as swing or take or pay options subject to daily as well as periodic constraints these contracts permit the option holder to repeatedly exercise the right to receive greater or smaller amounts of energy we extract market information from forward prices and volatilities and build a pricing framework for swing options based on a one factor mean reverting stochastic process for energy prices that explicitly incorporates seasonal effects we present a numerical scheme for the valuation of swing options calibrated for the case of natural gas

understanding the mechanisms through which an influential early childhood program boosted adult outcomes a growing literature establishes that high quality early childhood interventions targeted toward disadvantaged children have substantial impacts on later life outcomes little is known about the mechanisms producing these impacts this paper uses longitudinal data on cognitive and personality traits from an experimental evaluation of the influential perry preschool program to analyze the channels through which the program boosted both male and female participant outcomes experimentally induced changes in personality traits explain a sizable portion of adult treatment effects

risk premium in the uk natural gas forward market this report investigates the uk natural gas market and tests whether it is a fair game efficient forward market using forward contracts ranging from one to five months time to delivery the forward and spot price series are separately non stationary but cointegrated furthermore the forward prices are biased predictors of both the future spot and the 1 month ahead forward price the risk premium on the forward prices is positive as opposed to the us gas market where the risk premium was found to be negative in similar work moreover the analysis reveals that the storage model is an incomplete model for the relationship between the spot and forward prices however storage has a clear effect on this relationship an effect that appears to be non linear

optimal contracts with public ex post information abstract we are concerned with the value of public ex post information about a seller s costs to an initially uninformed buyer we derive necessary and sufficient conditions for a public ex post signal s s that is correlated with the risk neutral seller s costs to render the initial information asymmetry inconsequential to the buyer the first best outcome for the buyer is shown to be feasible if 1 the dimension of s is at least that of or 2 the conditional likelihood function of s given is for one of its realizations sj a strictly increasing function of and more concave in than is the seller s cost function

search theoretic models of the labor market a survey we survey the literature on search theoretic models of the labor market we show how this approach addresses many issues including the following why do workers sometimes choose to remain unemployed what determines the lengths of employment and unemployment spells how can there simultaneously exist unemployed workers and unfilled vacancies what determines aggregate unemployment and vacancies how can homogeneous workers earn different wages what are the tradeoffs firms face from different wages how do wages and turnover interact what determines efficient turnover we discuss various modeling choices concerning wage determination and the meeting process including recent models of directed search

the impact of education in rural ghana examining household labor allocation and returns on and off the farm most of the human capital literature pertaining to developing countries focuses on the returns to education in either farm work or wage work few studies examine how education affects the allocation of time between these activities this paper estimates the returns to education in farm and off farm work and consequently the role of education in determining the allocation of labor the results from this study show that off farm work has a much higher return to education than does farm work and suggest that this divergence in returns affects the allocation of labor in farm households between farm and off farm work

should we regulate financial information regulations that require asset issuers to disclose payoff relevant information to potential buyers sound like obvious measures to increase investor welfare but in many cases such regulations harm investors in an equilibrium model asset returns compensate investors for risk by making payoffs less uncertain disclosure reduces risk and therefore reduces return as high risk high return investments disappear investor welfare falls of course information is still valuable to each individual investor but acquiring information is like a prisoners dilemma each investor is better off with the information but collectively investors are better off if they remain uninformed the only cases in which providing information improves investors welfare are ones where there would otherwise be severe asymmetric information using a model of information markets the paper explores when such outcomes are likely to arise when we extend the model so that financial markets with information allocate the real capital stock more efficiently these conclusions do not change disclosure improves efficiency but more efficient firms do not have more risk and therefore do not offer investors higher return instead they simply command a higher price which only benefits the asset issuer since the efficiency gains are fully internalized by asset issuers who can choose to disclose without disclosure being mandatory the efficiency argument is not a logical rationale for regulation

long term swings and seasonality in energy markets abstract this paper introduces a two factor continuous time model for commodity pricing under the assumption that prices revert to a stochastic mean level which shows smooth periodic fluctuations over long periods of time we represent the mean reversion price by a fourier series with a stochastic component we also consider a seasonal component in the price level an essential characteristic of many commodity prices which we represent again by a fourier series we obtain analytical pricing expressions for futures contracts using futures price data on natural gas we provide evidence on the presence of long term fluctuations and show how to estimate the long term component simultaneously with a seasonal component using the kalman filter we analyse the in sample and out of sample empirical performance of our pricing model with and without a seasonal component and compare it with schwartz and smith 2000 model our findings show the in sample and out of sample superiority of our model with seasonal fluctuations thereby providing a simple and powerful tool for portfolio management risk management and derivative pricing

estimating labor supply and production decisions of self employed farm producers abstract this paper proposes a model oriented towards integrating farm households production and consumption decisions into a unified theoretical and econometric framework it is argued that in contrast with other forms of economic organization farm households utility and profit maximization decisions are not likely to be independent econometric estimation of a farm household model using canadian data suggests that utility and profit maximizing decisions are not indeed independent and moreover that there are significant gains in explanatory power and efficiency by estimating the consumption and production equations jointly

seasonal stochastic volatility implications for the pricing of commodity options many commodity markets contain a strong seasonal component not only at the price level but also in volatility in this paper the importance of seasonal behavior in the volatility for the pricing of commodity options is analyzed we propose a seasonally varying long run mean variance process that is capable of capturing empirically observed patterns semi closed form option valuation formulas are derived we then empirically study the impact of the proposed seasonal stochastic volatility model on the pricing accuracy of natural gas futures options traded at the new york mercantile exchange nymex and corn futures options traded at the chicago board of trade cbot our results demonstrate that allowing stochastic volatility to fluctuate seasonally significantly reduces pricing errors for these contracts

credit rating inflation and firms investments we analyze credit rating effects on firm investments in a rational bond financing game that features a feedback loop the credit rating agency cra inflates the rating providing a biased but informative signal to creditors creditors response to the rating affects the firm s investment decision and thus its credit quality which is reflected in the rating the cra might reduce ex ante economic efficiency which results solely from its strategic effect the cra assigns more firms high ratings and allows them to gamble for resurrection we derive empirical predictions on the determinants of rating standards and inflation and discuss policy implications

cash transfer programs and agricultural production the case of malawi cash transfer programs are increasingly utilized to combat poverty and hunger while building the human capital of future generations however they have been faulted by some for failing to build the productive capacity of current generations this article analyzes the impact of the malawi social cash transfer scheme on agricultural production the results show strong increases in ownership of productive agricultural assets in time devoted to household farms and in food types consumed from own production coupled with a sharp decrease in ganyu labor which is often used as a coping mechanism once food stores have been depleted these results are most likely achieved by helping farmers overcome credit and liquidity constraints this research shows that cash transfer programs can help the capacity of extremely poor farm households to expand agriculture production even if the goal of the program is focusing on other dimensions of poverty

rating the raters are reputation concerns powerful enough to discipline rating agencies abstract credit rating agencies cras are accused of bearing a strong responsibility for contributing to the subprime crisis by having been deliberately too lax in the ratings of some structured products in response to this accusation cras argue that such an attitude would be too dangerous for them since their reputation is at stake the objective of this article is to examine the validity of this argument within a formal model are reputation concerns sufficient to discipline rating agencies we show that the reputation argument only works when a sufficiency large fraction of the cra income comes from other sources than rating complex products by contrast when rating complex products becomes a major source of income for the cra we show that it is always too lax with a positive probability and inflates ratings with probability one when its reputation is good enough we provide some empirical support for this prediction by showing that ceteris paribus the proportion of subprime residential mortgage backed securities rmbs that were rated aaa by the three main cras indeed increased over the last eight years we analyze the policy implications of our findings and advocate for a new business model of cras that we call the platform pays model

state conditional fertilizer yield response on western kenyan farms 15 16 17 we acknowledge with gratitude support from the rockefeller foundation the united states agency for 18 international development usaid leadership enhancement in agriculture program leap and the 19 coupled natural and human systems program of the biocomplexity initiative of the national science 20 foundation through grant bcs 0215890 the world agroforestry center icraf graciously hosted 21 the lead author for part of the research and provided soil test results we are also grateful to james

monte carlo valuation of american options through computation of the optimal exercise frontier this paper introduces a monte carlo simulation method for pricing multidimensional american options based on the computation of the optimal exercise frontier we consider bermudan options that can be exercised at a finite number of times and compute the optimal exercise frontier recursively we show that for every date of possible exercise any single point of the optimal exercise frontier is a fixed point of a simple algorithm once the frontier is computed we use plain vanilla monte carlo simulation to price the option and obtain a low biased estimator we illustrate the method with applications to several types of options

ratings quality over the business cycle credit rating agencies cras have long held that reputational concerns discipline their behavior the value of reputation however depends on economic fundamentals that vary over the business cycle in a model of ratings incorporating endogenous reputation and a market environment that varies we find that ratings quality is countercyclical specifically a cra is more likely to issue less accurate ratings when fee income is high competition in the labor market for analysts is tough and securities default probabilities are low persistence in economic conditions can diminish our results while mean reversion exacerbates them the presence of naive investors reduces overall quality but quality remains countercyclical finally we demonstrate that competition among cras yields similar results

causal pathways of the productive impacts of cash transfers experimental evidence from lesotho abstract this paper has the double aim to study whether unconditional cash transfers have an impact on farm production and to look into the causal mechanisms through which government transfers produce productive impacts we use mediation analysis to identify the total effect of transfers on farm production and to isolate the influence of the labour channel from other transmission channels in particular we analyze whether changes in farm production are caused by transfer induced changes in the use of farm labour either by reallocating family labour between off and on farm work or by changes in the demand for hired labour or if other transmission channels are at work we find that cash transfers have a sizable impact on farm production but they do not lead to increased use of family or hired labour on the farm which implies that the productive impacts of cash transfers flow through other channels different from the labour one

short term variations and long term dynamics in commodity prices in this article we develop a two factor model of commodity prices that allows meanreversion in short term prices and uncertainty in the equilibrium level to which prices revert although these two factors are not directly observable they may be estimated from spot and futures prices intuitively movements in prices for long maturity futures contracts provide information about the equilibrium price level and differences between the prices for the short and long term contracts provide information about short term variations in prices we show that although this model does not explicitly consider changes in convenience yields over time this short term long term model is equivalent to the stochastic convenience yield model developed in gibson and schwartz 1990 we estimate the parameters of the model using prices for oil futures contracts and apply the model to some hypothetical oil linked assets to demonstrate its use and some of its advantages over the gibson schwartz model

how much of the labor in african agriculture is provided by women the contribution of women to labor in african agriculture is regularly quoted in the range of 60 to 80 percent using individual disaggregated plot level labor input data from nationally representative household surveys across six sub saharan african countries this study estimates the average female labor share in crop production at 40 percent it is slightly above 50 percent in malawi tanzania and uganda and substantially lower in nigeria 37 percent ethiopia 29 percent and niger 24 percent there are no systematic differences across crops and activities but female labor shares tend to be higher in households where women own a larger share of the land and when they are more educated controlling for the gender and knowledge profile of the respondents does not meaningfully change the predicted female labor shares the findings question prevailing assertions regarding substantial gains in aggregate crop output as a result of increasing female agricultural productivity

sequential causal models for the evaluation of labor market programs this article reviews inverse selection probability weighting to estimate dynamic causal effects a distribution theory based on sequential generalized method of moments estimation is proposed and the method is applied to a reevaluation of some parts of the swiss active labor market policy to obtain new results and discuss several issues about the implementation of the estimation procedure

the costs of motherhood an analysis using matching estimators we estimate the effect of motherhood on wages using matching we distinguish between net and direct effects the net effect includes the total wage costs whereas the direct represents the causal effect since covariates are likely affected by motherhood the latter effect is not immediately uncovered we therefore implement two strategies first we confine the analysis to consider sector specific treatment effects second we impose additive separability on the outcome equation we find negative net effects that vary little with sector the direct effect is small and negative in the public sector and insignificant in the private sector copyright 2006 john wiley sons ltd

of tournaments and temptations an analysis of managerial incentives in the mutual fund industry we test the hypothesis that when their compensation is linked to relative performance managers of investment portfolios likely to end up as losers will manipulate fund risk differently than those managing portfolios likely to be winners an empirical investigation of the performance of 334 growth oriented mutual funds during 1976 to 1991 demonstrates that mid year losers tend to increase fund volatility in the latter part of an annual assessment period to a greater extent than mid year winners furthermore we show that this effect became stronger as industry growth and investor awareness of fund performance increased over time

agricultural factor markets in sub saharan africa an updated view with formal tests for market failure this paper uses the recently collected living standard measurement study integrated surveys on agriculture initiative data sets from five countries in sub saharan africa to provide a comprehensive overview of land and labor market participation by agrarian households and to formally test for failures in factor markets under complete and competitive markets households can solve their consumption and production problems separately so that household factor endowments do not predict input demand this paper implements a simple theoretically grounded test of this separation hypothesis which can be interpreted as a reduced form test of factor market failure in all five study countries the analysis finds strong evidence of factor market failure moreover those failures appear general and structural not specific to subpopulations defined by gender or geography

peasant household behaviour with missing markets some paradoxes explained a model of peasant household behavior under varying degrees of household specific food and labor market failures is constructed to show that these structural features can explain several well known patterns of peasant response which have often been attributed to peculiar motives presumed specific to peasants the model explains sluggish response to cash crops prices and high instability in perceived food and labor scarcities the key role of manufactured consumer goods prices in stimulating peasants effort in cash crops production the effectiveness of taxation as opposed to incentives in stimulating cash crops production and the key role of technological change in food production to enhance cash crop production results are obtained analytically in the case of one market failure and by numerical simulation with more than one

causal pitfalls in the decomposition of wage gaps the decomposition of gender or ethnic wage gaps into explained and unexplained components often with the aim to assess labor market discrimination has been a major research agenda in empirical labor economics this article demonstrates that conventional decompositions no matter whether linear or nonparametric are equivalent to assuming a probably too simple model of mediation aimed at assessing causal mechanisms and may therefore lack causal interpretability the reason is that decompositions typically control for post birth variables that lie on the causal pathway from gender ethnicity which are determined at or even before birth to wage but neglect potential endogeneity that may arise from this approach based on the newer literature on mediation analysis we therefore provide more attractive identifying assumptions and discuss nonparametric identification based on reweighting

how does gender affect the adoption of agricultural innovations why do men and women adopt agricultural technologies at different rates evidence from ghana suggests that gender linked differences in the adoption of modern maize varieties and chemical fertilizer result from gender linked differences in access to complementary inputs this finding has important policy implications because it suggests that ensuring more widespread and equitable adoption of improved technologies may not require changes in the research system but rather introduction of measures that ensure better access for women to complementary inputs especially land labor and extension services

a multi factor model with time varying and seasonal risk premiums for the natural gas market abstract in this paper we develop a quantitative model of the us natural gas market that explores its multi factor structure and its time varying and seasonal risk premiums with weekly spot and futures prices we show that three factors are preferred to describe the futures term structure and the time varying risk premiums are also significant moreover we found that the market implies a seasonal risk premium with two peaks and troughs in one year which is important to correctly price the futures by maturity month finally we link this seasonal risk premium to the uncertainty of the us natural gas demand and find a positive relationship between them these results reveal the complex aspect of the market and may have useful applications for other commodity sectors

household composition labor markets and labor demand testing for separation in agricultural household models this paper tests the separation of farm labor supply and labor demand decisions using the observation that household composition is an important determinant of farm labor use with nonseparation after assessing the conditions under which the test has power against several alternatives an empirical model is developed to test the proposition that farm employment is independent of family composition the model is estimated on a data set from rural java the null hypothesis that farm labor allocation decisions are independent of household structure is not rejected the results are robust to different specifications of the labor demand function copyright 1992 by the econometric society

gender agricultural production and the theory of the household virtually all models of the household assume that the allocation of resources is pareto efficient within many african households agricultural production occurs on many plots controlled by different members of the household pareto efficiency implies that factors should be allocated efficiently across these plots i find in contrast that plots controlled by women are farmed much less intensively than similar plots within the household controlled by men the estimates imply that about 6 percent of output is lost because of inefficient factor allocation within the household the paper suggests a new approach to modeling intrahousehold allocation consistent with the empirical results

uk gas markets the market price of risk and applications to multiple interruptible supply contracts we employ the schwartz and smith schwartz e and j smith 2000 short term variations and long term dynamics in commodity prices management science 46 893 911 model to explore the dynamics of the uk gas markets we discuss in detail the short term and long term market prices of risk borne by the market players and how deviations from expected cyclical storage affect the short term market price of risk finally we illustrate an application of the model by pricing interruptible supply contracts that are currently traded in the uk

career concerns of mutual fund managers we examine the labor market for mutual fund managers using data from 1992 1994 we find that termination is more performance sensitive for younger managers we identify possible implicit incentives created by the termination performance relationship the shape of the termination performance relationship may give younger managers an incentive to avoid unsystematic risk direct effects of portfolio composition may also give younger managers an incentive to herd into popular sectors consistent with these incentives we find that younger managers hold less unsystematic risk and have more conventional portfolios promotion incentives and market responses to managerial turnover are also studied

modelling trends in food market integration method and an application to tanzanian maize markets abstract pushed by increasing availability of price data and extensive market liberalisation efforts in many developing countries research on food market integration has evolved rapidly over the last two decades empirical methods to measure market integration diverged in two directions on the one hand there is the parity bounds model pbm using a switching regressions technique while on the other hand the use of threshold autoregressive tar models has been proposed this article provides a discussion on the two methods and argues that tar models are better able to capture the dynamics of the arbitrage process underlying interconnected markets furthermore we extend the standard tar model to include a time trend in both the threshold and the adjustment parameter using weekly maize price data on seven selected markets in tanzania we illustrate how both transaction cost and the speed of adjustment have changed during the nineties

ratings shopping and asset complexity a theory of ratings inflation abstract many identify inflated credit ratings as one contributor to the recent financial market turmoil we develop an equilibrium model of the market for ratings and use it to examine possible origins of and cures for ratings inflation in the model asset issuers can shop for ratings observe multiple ratings and disclose only the most favorable before auctioning their assets when assets are simple agencies ratings are similar and the incentive to ratings shop is low when assets are sufficiently complex ratings differ enough that an incentive to shop emerges thus an increase in the complexity of recently issued securities could create a systematic bias in disclosed ratings despite the fact that each ratings agency produces an unbiased estimate of the asset s true quality increasing competition among agencies would only worsen this problem switching to an investor initiated ratings system alleviates the bias but could collapse the market for information

the production effects of agricultural income support policies under uncertainty this analysis decomposes the production impacts of income support programs into wealth insurance and coupling effects under the usual assumptions about preferences the wealth and insurance effects of many support programs increase optimal input levels even for supposedly decoupled programs if the program is coupled in the usual sense then all three effects often act in the same direction it is concluded that studies of trade and domestic policy reform in stochastic environments should consider insurance and wealth effects the derivative conditions required to obtain results are also subjected to scrutiny simulations for an iowa corn producer confirm the comparative statics

contracting to compete for flows abstract we present a model in which asset managers design their contracts to attract flows of investor capital we find that they make their contracts depend on public information e g credit ratings or benchmark indices as a way to attract flows rather than as a way to mitigate incentive problems as has been emphasized in the literature unfortunately asset managers competition for flows triggers a race to the bottom asset managers use public information in their contracts even though it is socially inefficient this inefficiency arises because contracting on public information prevents risk sharing

a microeconometric evaluation of the active labour market policy in switzerland in the second part of the 1990 s switzerland conducted an ambitious active labour market policy almp encompassing a wide variety of programmes we evaluate the effects of these programmes on the individual employment probability of potential participants our econometric analysis uses unusually informative data origi nating from administrative unemployment and social security records we apply a matching es timator adapted for the case of multiple programmes we find substantial positive effects for one particular programme that is a unique feature of the swiss almp it consists of a wage subsidy for temporary jobs in the regular labour market that would otherwise not be taken up by the unemployed we also find large negative effects for traditional employment programmes oper ated in sheltered labour markets for training courses the results are mixed doi 10 1111 1468 0297 00072 download internet appendix pdf 2 590 kb

testing in models of asymmetric information this paper explores the role of testing in models of asymmetric information we demonstrate conditions under which testing for underlying characteristics can overcome adverse selection problems and lead to a full information competitive equilibrium this paper provides a more general statement of mirrlees result on the optimal use of infinite fines where testing cannot fully resolve the problems associated with asymmetric information we outline the source of the difficulties our results developed in the context of a labour market can be directly extended to other environments in problems with asymmetric information testing to discover an agent s chosen action or underlying characteristics may significantly reduce the cost of moral hazard and adverse selection

endogenous punishments in agency with verifiable ex post information the article studies an adverse selection model in which a contractible imperfect signal on the agent s type is revealed ex post the agent is wealth constrained which implies that the maximum penalty depends on the contracted transaction e g the volume of trade first we show that the qualitative effects of the signal can be unambiguously tied to the nature of the problem e g whether the agent is in a buyer or a seller position second the distortions caused by informational asymmetries may become more severe although more information is now available finally the signal can actually serve to increase the agent s informational rents

does it all add up benchmarks and the compensation of active portfolio managers in this article the authors examine theoretically the use of benchmark portfolios in the compensation of privately informed portfolio managers they find that the use of a benchmark and particularly the types of benchmarks often observed in practice cannot be easily rationalized specifically commonly used benchmark adjusted compensation schemes are generally inconsistent with optimal risk sharing and do not lead to the choice of an optimal portfolio for the investor moreover benchmarks do not help in solving potential contracting problems such as inducing the manager to expend effort or trying to screen out uninformed managers copyright 1997 by university of chicago press

on the comparison of schwartz and smith s two and three factor models on commodity prices since schwartz and smith 2000 published their study on two factor model on commodity prices many studies have used this model and others have extended it the authors also proposed the three factor model due to the poor fitting of the two factor one on long term futures prices at that time the authors had only long term prices from a private source to calibrate test and compare these models no public data on long term future contracts were available on the other hand during the last decade the commodity prices soared as did the liquidity of long term contracts this means that the interest of the agents in the management of their risk on long term positions increased the same way and this is the motivation for this study in this article we revisit the comparison between two and three factor models using public data for short and long term contracts we use up to the 67 month ahead contract we also provide a detailed derivation of the three factor model differently from that of the original a

product differentiation search costs and competition in the mutual fund industry a case study of s p 500 index funds we investigate the role that non portfolio fund differentiation and information search frictions play in creating two salient features of the mutual fund industry the large number of funds and the sizeable dispersion in fund fees in a case study we find that despite the financial homogeneity of s p 500 index funds this sector exhibits the fund proliferation and fee dispersion observed in the broader industry we show how extra portfolio mechanisms explain these features these mechanisms also suggest an explanation for the puzzling late 1990s shift in sector assets to more expensive and often newly entered funds an influx of highinformation cost novice investors

behavioural and material determinants of production relations in agriculture in this essay we develop a framework for analysing the major institutions governing the production and exchange of output and the primary factors of production in rural areas the analysis incorporates general considerations of risk and information constraints jointly with the principal material attributes of agriculture and of agricultural production factors the framework is used to analyse barriers to the existence of the major intertemporal and factor markets it is applied specifically to land scarce environments for which it provides an internally consistent explanation for many of the well documented institutional features of such settings in addition the analysis provides new implications for among other phenomena the inter relationships among ownership holdings operational scale family size and factor productivity for the scarcity of animal rental markets and use of animals as collateral for the renting out of land by small landowners and for the existence of plantations for certain crops

rural nonfarm employment and farming household level linkages this article introduces the articles in agricultural economics vol 40 no 2 march 2009 first we introduce their objectives in a brief review of existing literature on developing country trends in rural income diversification in particular rural nonfarm employment rnfe and its impact on farm technology choice in crops and livestock and thus on agricultural modernization and diversification then we preview the key points of the articles which use distinctive primary datasets from albania bulgaria china india mexico nigeria the philippines senegal and vietnam to document the impacts of rnfe and their implications for farm technology and farm activity

optimal hedging under biased energy futures markets abstract optimal futures hedging positions for those agents trying to maximize their expected utility will depend on their view about the evolution of the market and on how risk adverse they are the most risk adverse agents will probably decide to full cover their positions but when a futures bias exists hedgers with moderate or low degree of risk aversion can alter their strategy depending on the expected gains in futures markets in our application to the uk natural gas market we find a statistically significant time varying negative futures bias that can be forecasted with confidence as a result of this bias most effective and best performing hedging strategies for moderate risk averse agents are those involving short long hedging in winter summer with a hedging ratio above below the minimum variance hedge ratio these findings are of great interest to practitioners in the uk natural gas markets and the methodology can be extrapolated to other energy markets

why do tougher caseworkers increase employment the role of programme assignment as a causal mechanism abstract previous research found that less accommodating caseworkers are more successful in placing unemployed workers into employment this paper explores the causal mechanisms behind this result using semi parametric mediation analysis analyzing rich linked job seeker caseworker data for switzerland we find that the positive employment effects of less accommodating caseworkers are not driven by a particularly effective mix of labor market programs but rather by other dimensions of the counseling process possibly including threats of sanctions and pressure to accept jobs

agricultural decisions after relaxing credit and risk constraints the investment decisions of small scale farmers in developing countries are conditioned by their financial environment binding credit market constraints and incomplete insurance can limit investment in activities with high expected profits we conducted several experiments in northern ghana in which farmers were randomly assigned to receive cash grants grants of or opportunities to purchase rainfall index insurance or a combination of the two demand for index insurance is strong and insurance leads to significantly larger agricultural investment and riskier production choices in agriculture the binding constraint to farmer investment is uninsured risk when provided with insurance against the primary catastrophic risk they face farmers are able to find resources to increase expenditure on their farms demand for insurance in subsequent years is strongly increasing with the farmer s own receipt of insurance payouts with the receipt of payouts by others in the farmer s social network and with recent poor rain in the village both investment patterns and the demand for index insurance are consistent with the presence of important basis risk associated with the index insurance imperfect trust that promised

farm consumption behavior in the presence of uncertainty and restrictions on credit farm consumption behavior has an important indirect role in determining the ability of farms to invest and grow in this paper i examine the effect on farm consumption behavior of the presence of quantitative restrictions on farm borrowing using a form of the life cycle model which allows for both consumption and production by the household the effect of borrowing restrictions on consumption behavior is tested econometrically for a sample of dutch farm households the results suggest that the life cycle model without borrowing restrictions is rejected by the data

evaluating the risk premium in the u s a natural gas market evidence from low price regime abstractin recent years the u s a natural gas market has seen enormous changes the expectations of abundant supply of shale gas and the slow u s a economic recovery have pushed gas prices below us 4 mmbtu although shale gas is a new promising source of unconventional energy investors face uncertain investment plans in this study we investigate the risk premium by comparing behaviour before and after the change point in agents risk perception unlike traditional empirical research on risk premium we use the parametric two factor model of schwartz and smith 2000 to evaluate the implied risk premium term structure from futures prices traded on the new york mercantile exchange nymex we compare our findings with other empirical results and find that the change point lies at the beginning of the low price regime when we compare periods before and after the change point we observe that the risk premium changed not only in sign but also in magnitude

hedging size risk theory and application to the us gas market abstract many corporate commitments exhibit a combined financial exposure to both market prices and idiosyncratic size components e g volume load or business turnover we design a customized contract to optimally mitigate the risk of joint fluctuations in price and size terms the hedge is sought out among contingent claims written on price and any quoted index that is statistically dependent on commitment size closed form solutions are derived for the optimal custom hedge pay off and for the asset holdings of two market strategies one based on price linked forwards the other based on price linked and index linked forwards analytical hedges are obtained using a stylized lognormal market model detailed comparative statics provide a thorough analysis of optimal hedging pay off functions performance assessment is conducted in the context of the us gas market and a prototypical urban region results suggest that hedging through suitable custom claims written on price and an additional index significantly outperforms standard price based as well as mixed price index forward hedging alternatives our optimal custom hedge could be adopted as a benchmark for the relative assessment of any risk management solution

full extraction of the surplus in bayesian and dominant strategy auctions we consider auctions for a single indivisible object in the case where the bidders have information about each other which is not available to the seller we show that the seller can use this information to his own benefit and we completely characterize the environ ments in which a well chosen auction gives him the same expected payoff as that obtainable were he able to sell the object with full information about each bidder s willingness to pay we provide this characterization for auctions in which the bidders have dominant strate gies and for those where the relevant equilibrium concept is bayesian nash in both set ups the existence of these auctions hinges on the possibility of constructing lotteries with the correct properties we consider the situation in which an agent the seller possesses one indivisible unit of a good to which he attaches no value but the good has value to a number of potential buyers and its transfer to one of them would increase social welfare in particular the transfer to the buyer with the highest valuation maximizes social welfare in this paper we completely characterize environments in which the seller can design an auction that will enable him to capture for himself the full increase in social welfare induced by the transfer of the good to the bidder with the highest willingness to pay if the seller had full information about the reservation prices of potential buyers his optimal selling strategy would be very simple he would announce a price equal or very close to the highest reservation value the optimal strategy for the bidder with the highest evaluation would be to accept the offer note that we are treating a situation in which the seller can commit himself to a price as a result of the exchange the utility of the seller increases by the full amount of the increase in social welfare and he has been able to fully extract the surplus in many circumstances however a seller has only imperfect knowledge of the buyers willingnesses to pay in this case he must find some mechanism or auction which will enable him to maximize his benefit from the sale of the object the auction literature starts with this observation and shows how the seller can by an astute choice of auction extract the largest possible fraction of the surplus in general the literature has shown that this proportion is strictly less than one in some circumstances the bidders will have information about each other which is not available to the seller for instance in auctions for petroleum drilling rights bidders know the results of geological tests which they have

analytical pricing of discretely monitored asian style options theory and application to commodity markets we compute an analytical expression for the moment generating function of the joint random vector consisting of a spot price and its discretely monitored average for a large class of square root price dynamics this result combined with the fourier transform pricing method proposed by carr and madan carr p madan d 1999 option valuation using the fast fourier transform journal of computational finance 2 4 summer 61 73 allows us to derive a closed form formula for the fair value of discretely monitored asian style options our analysis encompasses the case of commodity price dynamics displaying mean reversion and jointly fitting a quoted futures curve and the seasonal structure of spot price volatility four tests are conducted to assess the relative performance of the pricing procedure stemming from our formulae empirical results based on natural gas data from nymex and corn data from cbot show a remarkable improvement over the main alternative techniques developed for pricing asian style options within the market standard framework of geometric brownian motion

portfolio performance and agency the evaluation and compensation of portfolio managers is an important problem for practitioners optimal compensation will induce managers to expend eort to generate information and to use it appropriately in an informed portfolio choice our general model points the way towards analysis of optimal performance evaluation and contracting in a rich model optimal contracting in the model includes an important role for portfolio restrictions that are more complex than the sharing rule the agent s compensation gives the agent approximately to a benchmark return plus an incentive fee equal to a portfolio measure that is approximately the excess of return above the benchmark this measure is often used by practitioners but is simpler than the jensen measure and other measures commonly recommended in the academic literature in addition to the excess return above the xed benchmark the manager is given some additional incentive to take a position that deviates from the benchmark to remove an incentive to tend towards being a closet indexer ecient contracting involves restrictions on what portfolio strategies can be pursued and prior communication of the information gathered

information reliability and welfare a theory of coarse credit ratings abstract an enduring puzzle is why credit rating agencies cras use a few categories to describe credit qualities lying in a continuum even when ratings coarseness reduces welfare we model a cheap talk game in which a cra assigns positive weights to the divergent goals of issuing firms and investors the cra wishes to inflate ratings but prefers an unbiased rating to one whose inflation exceeds a threshold ratings coarseness arises in equilibrium to preclude excessive rating inflation we show that competition among cras can increase ratings coarseness we also examine the welfare implications of regulatory initiatives

how much should we pay for interconnecting electricity markets a real options approach abstract an interconnector is an asset that gives the owner the option to transmit electricity between two locations in financial terms the value of an interconnector is the same as a strip of real options written on the spread between power prices in two markets we model the spread based on a seasonal trend mean reverting gaussian process and mean reverting jump process and express the value of these real options in closed form the valuation tool is applied to five pairs of european neighboring markets to value a hypothetical one year lease of the interconnector using different assumptions about the seasonal component of the spread and different liquidity caps which proxy for the depth of the interconnected power markets we derive no arbitrage lower bounds for the value of the interconnector in terms of electricity futures contract and find that depending on the depth of the market the jumps in the spread can account for between 1 and 40 of the total value of the interconnector the two markets where an interconnector would be most resp least valuable are germany and the netherlands resp france and germany finally we provide rules of thumb to interpret the different interconnector values

multiple regime spatial price transmission with an application to maize markets in southern africa conventional threshold models of price transmission allow for different speeds of adjustment to equilibria depending on the magnitude of price differentials between markets however these models typically assume only one underlying long run equilibrium price relationship in this article we develop a framework for allowing multiple equilibria and multiple speeds of adjustment with regime separation depending on the magnitude of trade flows between regions rather than the magnitude of price differentials applying this framework to maize price transmission between south africa and zambia shows no transmission during periods of high imports when the government was heavily involved in maize importation but stronger transmission during periods of low imports when the government was not importing copyright 2012 oxford university press

the relation between farm size and farm productivity the role of family labor supervision and credit constraints abstract the paper shows that if the performance of hired farmhands is affected by supervision from family members and if the availability of credit is dependent on the amount of land owned then a systematic positive or negative relationship between per acre yields and farm size will prevail a model with no supervision effects on labor productivity would predict that yields are unaffected by farm size the paper also investigates the relation between land utilization and owned holding size when land rental possibilities are limited results are shown to be compatible with various observed patterns in ldcs