on the transmission of world agricultural prices two questions are asked about the relationship between domestic prices and world prices of agricultural commodities are variations in world prices transmitted to domestic prices domestic prices are regressed on world prices in various forms taking into account the possible effects of exchange rates and inflation the empirical analysis is based on data from the food and agriculture organization of the united nations for 58 countries from 1968 78 and for the countries of the european community from 1961 85 the results show that most of the variations in world prices are transmitted and that they constitute the dominant component in the variations of domestic prices

world poverty and the role of agricultural technology direct and indirect effects agricultural technology can help reduce poverty through direct and indirect effects direct effects are gains for the adopters while indirect effects are gains derived from adoption by others leading to lower food prices employment creation and growth linkage effects conceptualising and measuring these effects is highly complex yet is needed for each region if technology is to be used as an effective instrument for poverty reduction we propose a methodology for doing this in the context of computable general equilibrium modelling and apply it to archetype models for africa asia and latin america results show that the dominant effect of technology on poverty is through direct effects in africa indirect agricultural employment effects in asia and linkage effects through the rest of the economy in latin america in each case increasing the poverty reduction effect through the targeting of technology across crops and through complementary rural development programmes is also explored

limit theorems for markets with sequential bargaining this paper models trade as a non coopertative strategic game played at an inlinite sequence of dates a single indivisible commodity is traded buyers and sellers have transferable utility and are characterized by their reservation utilities they meet at random and bargain over the price at which a single unit of the good will be exchanged under a variety of circumstances it is shown that as the costs of search and bargaining become negligible the outcome of the game converges to the competitve flow equilibrium even when there is complete information journal of economic literature classification numbers 022 19x7

decentralized trading strategic behaviour and the walrasian outcome for a market with a finite number of agents pairwise matching and bargaining it is shown that even when the market is frictionless the equilibrium is not necessarily competitive it depends on the amount of information agents use if their behaviour is conditioned only on the sets of agents present and the time the competitive solution is the unique subgame perfect equilibrium if agents have full information and condition their behaviour on some of it there are also noncompetitive equilibria in which behaviour depends on specific information such as the identity of the trading partner and past events

price relations between export and domestic rice markets in thailand abstract many rice importing countries argue that rice exporting nations isolate their domestic markets through the use of stabilization pricing policies which cause international rice markets to become excessively volatile for the argument to hold any weight price transmission between exporting countries domestic and export markets should be unidirectional whereby export prices are driven by domestic prices but domestic prices are not affected by export prices the study tests the hypothesis on thailand traditionally the world s largest rice exporter the results from the causality tests are not entirely clear however the results from the impulse response functions show that while the shocks originating in the domestic market are higher in magnitude in the export market in the short run the shocks originating in the export market are more persistent in the domestic market this suggests that although thailand s domestic policies are somewhat effective in the immediate months after the shock they allow price transmission from its export market to transfer over to its domestic market in the long run the results therefore imply that thailand s domestic pricing programs are not heavily distorting world rice markets

matching markets with adverse selection abstract this paper considers a market with adverse selection in the spirit of rothschild and stiglitz quart j econ 90 1976 629 the major departure from existing approaches is that we model a decentralized market that is open ended and constantly refilled by new participants e g by new workers and firms in the case of a labor market the major novelty of this approach is that the distribution of types in the market becomes an endogenous variable which is jointly determined with equilibrium contracts as frictions become small we show that the least cost separating contracts are always supported as an equilibrium outcome regardless of the distribution of types among entrants moreover we derive conditions under which this outcome is also unique

bargaining and markets complexity and the competitive outcome abstract rubinstein and wolinsky rev econ stud 57 1990 63 78 consider a simple decentralised market game in which agents meet randomly or voluntarily and bargain over the terms of trade they show that any individually rational price can be sustained as a sequential equilibrium even though the model has a unique competitive outcome here i consider rubinstein and wolinsky s model and show that if complexity costs of implementing strategies enter players preferences together with the standard payoff in the game then every equilibrium is stationary markov and induces the unique competitive price thus i demonstrate that aversion to complexity may provide a justification for the competitive outcome

do rice prices follow a random walk evidence from markov switching unit root tests for asian markets this study revisits the issue of mean reversion in the import rice prices of six asian countries over the period between 1995 and 2015 augmented dickey fuller tests with a conventional linear regression model support the presence of a unit root in the levels of the price data however when regressions allow for markov switching in coefficients and variances to capture periodic shifts in levels and volatilities there is strong evidence against the unit root null hypothesis in favor of stationarity over much of the observation period

screening in a matching market contract design under incomplete information is often analysed in a bilaterally monopolistic setting if the informed party s reservation value does not depend on its private information its type it is a standard result that the uninformed side offers low types distorted contracts to reduce the information rent left to high types we challenge this result by embedding contract design in a matching market environment we consider a market where players meet pairwise and where in each match either side may be chosen to make a take it or leave it offer as frictions become sufficiently low we find that the set of equilibria is independent of whether there is complete or incomplete information in particular all contracts are free of distortions

dynamic matching and bargaining games a general approach this paper presents a new characterization result for competitive allocations in quasilinear economies this result is informed by the analysis of non cooperative dynamic search and bargaining games such games provide models of decentralized markets with trading frictions a central objective of this literature is to investigate how equilibrium outcomes depend on the level of the frictions in particular does the trading outcome become walrasian when frictions become small existing specifications of such games provide divergent answers the characterization result is used to investigate what causes these differences and to generalize insights from the analysis of specific search and bargaining games

the rate of convergence to perfect competition of matching and bargaining mechanisms abstract we study the steady state of a market with incoming cohorts of buyers and sellers who are matched pairwise and bargain under private information a friction parameter is the length of the time period until the next meeting we provide a necessary and sufficient condition for the convergence of mechanism outcomes to perfect competition at the linear rate in which is shown to be the fastest possible among all bargaining mechanisms the condition requires that buyers and sellers always retain some bargaining power the bargaining mechanisms that satisfy this condition are called nonvanishing bargaining power nbp mechanisms simple random proposer take it or leave it protocols are nbp while k double auctions k da are not we find that k das have equilibria that converge to perfect competition at a linear rate converge at a slower rate or even do not converge at all

dynamic matching two sided incomplete information and participation costs existence and convergence to perfect competition consider a decentralized dynamic market with an infinite horizon and participation costs in which both buyers and sellers have private information concerning their values for the indivisible traded good time is discrete each period has length and each unit of time continuums of new buyers and sellers consider entry traders whose expected utility is negative choose not to enter within a period each buyer is matched anonymously with a seller and each seller is matched with zero one or more buyers every seller runs a first price auction with a reservation price and if trade occurs both the seller and the winning buyer exit the market with their realized utility traders who fail to trade continue in the market to be rematched we characterize the steady state equilibria that are perfect bayesian we show that as converges to zero equilibrium prices at which trades occur converge to the walrasian price and the realized allocations converge to the competitive allocation we also show the existence of equilibria for sufficiently small provided the discount rate is small relative to the participation

land allocation in hyv adoption models an investigation of alternative explanations microeconomic theory provides four competing explanations for partial land allocation to new and traditional seed varieties in hyv adoption decisions input fixity portfolio selection safety first behavior and learning testing a general model that contains each as a special case suggests that they are jointly most likely to explain land allocation in the hyv adoption decisions of malawian smallholders yet when each explanation is tested to the exclusion of the others as is usually the case in the literature competing hypotheses are individually significant results suggest that employing approaches based on single explanations may lead to inappropriately narrow conclusions

managing food price risks and instability in a liberalizing market environment overview and policy options abstract managing food price risks and instability is a major challenge in the midst of ongoing food market reforms key findings from the papers in this special volume revolve around five broad areas i the sources and magnitudes of food price instability in different country contexts ii the economic and social costs stemming from price instability iii the lessons from food market reforms to date iv the design of policy reforms in ways that promote efficient and stable market development and protect the interests of the poor and v potential policy responses to food price instability in a liberalizing market environment

peanut research and poverty reduction impacts of variety improvement to control peanut viruses in uganda a procedure is developed and applied for predicting ex ante impacts of agricultural research on aggregate poverty using as an example the poverty reducing impact of peanut research in uganda market level information on economic surplus changes is combined with a procedure for allocating income changes to individual households characteristics of farmers that affect their likelihood of technology adoption are used to create a technology adoption profile associated changes in poverty resulting from adoption are computed using poverty indices predicted income changes at the household level are aggregated to the market level and reconciled with calculations of economic surplus changes

why do parties use primaries political selection versus candidate incentives this paper contrasts empirically two possible explanations for the party decision to use primaries desire to improve political selection selection effect or desire to increase political competition and incentives among candidates incentive effect using a simple model of endogenous primaries i show that each explanation implies a different relation between primary adoption and the strength of partisan support i estimate this relation using the case of latin american presidential primaries and find robust evidence that the incentive effect dominates the selection effect

price discovery in a matching and bargaining market with aggregate uncertainty abstract we introduce aggregate uncertainty into a rubinstein and wolinsky 1985 type dynamic matching and bilateral bargaining model the market can be either in a high state where there are more buyers than sellers or in a low state where there are more sellers than buyers traders do not know the state they randomly meet each other and bargain by making take it or leave it offers the only information transmitted in a meeting is the time a trader spent on the market there are two kinds of search frictions time discounting and exogenous exit we find that as the search frictions vanish the market discovers the competitive price quickly the prices offered in equilibrium converge in expectation to the true state walrasian price at the rate linear in the total search friction this rate is the same as it would be if the state were commonly known

mechanism design by competing sellers a dynamic model with many sellers and buyers is constructed agents failing to trade may trade in the next period an equilibrium is found where sellers hold identical auctions and buyers randomize over the sellers they visit the distribution of buyer valuations is endogenous an auction with efficient reserve is an optimal mechanism from each seller s point of view in spite of the ability of any seller to alter the distribution of buyer types participating in the seller s mechanism by altering the mechanism copyright 1993 by the econometric society

crop failure price regulation and emergency imports of japan s rice sector in 1993 in 1993 an extraordinarily cool summer in japan brought about low rice yields which caused considerable disturbances to the rice markets japan imported a large amount of rice as an emergency measure two controversies about japan s rice policies were raised particularly in that period the first centred on the effectiveness of the price regulation policies in stabilizing rice prices and farmers incomes the second involved the newspapers arguments that the emergency imports harmed other countries especially developing countries these controversies were examined with a world trade computable general equilibrium model

complexity and competition extensive form market games typically have a large number of noncompetitive equilibria in this paper we argue that the complexity of noncompetitive behavior provides a justification for competitive equilibrium in the sense that if rational agents have an aversion to complexity at the margin then maximizing behavior will result in simple behavioral rules and hence in a competitive outcome for this purpose we use a class of extensive form dynamic matching and bargaining games with a finite number of agents in particular we consider markets with heterogeneous buyers and sellers and deterministic exogenous sequential matching rules although the results can be extended to other matching processes if the complexity costs of implementing strategies enter players preferences lexicographically with the standard payoff then every equilibrium strategy profile induces a competitive outcome

markov equilibria in dynamic matching and bargaining games abstract rubinstein and wolinsky rev econ stud 57 1990 63 show that a simple homogeneous market with exogenous matching has a continuum of non competitive perfect equilibria however the unique markov perfect equilibrium of this model is competitive by contrast in the more general case of heterogeneous markets even the markov property is not enough to guarantee the perfectly competitive outcome we define a market game that allows for heterogeneous values on both sides of the market and exhibit a number of examples of non competitive markov perfect equilibria with and without discounting unlike the homogeneous case these equilibria allow for inefficient trades and for trade at non uniform prices the non competitive equilibrium may be unique

an evaluation of the swedish system of active labour market programmes in the 1990s we investigate the presence of short and long term effects from joining a swedish labor market program vis a vis more intense job search in open unemployment overall the impact of the program system is found to have been mixed joining a program has increased employment rates among participants a result robust to a misclassification problem in the data on the other hand it has also allowed participants to remain significantly longer on unemployment benefits and more generally in the unemployment system this being particularly the case for those entitled individuals entering a program around the time of their unemployment benefits exhaustion

the impact of improved maize varieties on poverty in mexico a propensity score matching approach summary this study examines the adoption of improved maize germplasm in oaxaca and chiapas in mexico it employs a propensity score matching approach to analyze the impact of the adoption of improved maize varieties on household income and poverty reduction using cross sectional data of 325 farmers from the two regions the findings reveal a robust positive and significant impact of improved maize variety adoption on farm household welfare measured by per capita expenditure and poverty reduction specifically the empirical results suggest that adoption of improved maize varieties helped raise household per capita expenditure by an average of 136 173 mexican pesos thereby reducing their probability of falling below the poverty line by roughly 19 31

the role of private information in dynamic matching and bargaining can it be good for efficiency abstract we consider a private information replica of the dynamic matching and bargaining model of mortensen and wright 2002 we find that private information typically deters entry but the welfare can actually be higher under private information

prices delay and the dynamics of trade we characterize the dynamics of trading patterns and market composition when trade is bilateral finding a trading partner is costly prices are determined by bargaining and preferences are private information we show that equilibrium is inefficient and exhibits delay as sellers price discriminate between buyers with different values as frictions vanish transaction prices are asymptotically competitive and the welfare loss of inefficient trading approaches zero even though the trading patterns continue to be inefficient and delay persists journal of economic literature classification numbers d40 d50

convergence to perfect competition of a dynamic matching and bargaining market with two sided incomplete information and exogenous exit rate abstract consider a decentralized dynamic market with an infinite horizon and incomplete information in which buyers and sellers values for the traded good are private and independently drawn time is discrete each period has length and each unit of time a large number of new buyers and sellers enter the market within a period each buyer is matched with a seller and each seller is matched with zero one or more buyers every seller runs a first price auction with a reservation price and if trade occurs the seller and winning buyer exit with their realized utility traders who fail to trade either continue in the market to be rematched or exit at an exogenous rate we show that in all steady state perfect bayesian equilibria as approaches zero equilibrium prices converge to the walrasian price and realized allocations converge to the competitive allocation

walras retrouve decentralized trading mechanisms and the competitive price we extend the standard analysis of decentralized markets to allow for the possibility that traders interact simultaneously with more than one trader on the opposite side of the market in contrast with the literature we reconcile the walrasian equilibrium with the outcome of decentralized strategic trade we show that there exist generic matching technologies that determine local market conditions such that as market frictions vanish the equilibrium price is the one that would result in the static walrasian market our analysis highlights the importance of local market conditions for the determination of equilibrium prices

learning and price discovery in a search market we introduce learning into an otherwise standard two sided search and bargaining market there is uncertainty about the price distribution due to uncertainty about an underlying exogenous state of relative demand in the high state buyers are on the long side otherwise they are on the short side in equilibrium prices are on average higher in the high state individual agents learn about the distribution while searching agents typically start out by experimenting with a tough bargaining position buyers may initially insist on a low price and sellers on a high price after successive failures to trade agents become increasingly pessimistic about the market conditions and soften their bargaining stance when frictions are small equilibrium transaction prices are approximately market clearing despite aggregate demand being unknown thus the search and bargaining procedure enables price discovery in a decentralized market

does agricultural trade liberalization increase risks of supply side uncertainty effects of productivity shocks and export restrictions on welfare and food supply in japan abstract agriculture is the focus of much contention in free trade negotiations the japanese government is against liberalizing the rice trade on the grounds that it would threaten national food security in the events of such shocks as crop failure and embargoes trade liberalization is expected to make the japanese economy more dependent upon food imports and thus more susceptible to these risks using a computable general equilibrium model with a monte carlo simulation we quantify the welfare impacts of productivity shocks and export quotas by major rice exporters to japan and found little evidence of japan suffering from such shocks

competitive pricing and efficiency in search equilibrium we consolidate and generalize some results on price determination and efficiency in search equilibrium extending models by rubinstein and wolinsky and by gale heterogeneous buyers and sellers meet according to a general matching technology and prices are determined by a general bargaining condition when the discount rate r and search costs converge to 0 we show that prices in all exchanges are the same and equal the competitive market clearing price given positive search costs efficiency obtains iff bargaining satisfies hosios condition and r 0 when prices are set by third party market makers however we show that search equilibrium is necessarily efficient

why so much stability one of duncan black s 1958 more important contributions was a classically simple proof that with complex issues and majority voting a stable outcome is unlikely this very simple proof that there would normally be no motion which can get a majority against all others and hence that any possible outcome is dominated by another has been elaborated and made more precise by later work without most improbable conditions endless cycling would be expected this is particularly true when logrolling is present as it normally is if we look at the real world however we observe not only is there no endless cycling but acts are passed with reasonable dispatch and then remain unchanged for very long periods of time thus theory and reality seem to be not only out of contact but actually in sharp conflict it is the purpose of this article to demonstrate that our existing theory when properly looked at does indeed imply a relatively stable outcome to voting in some cases however this stability will not be a true equilibrium because a random member of a large set will be chosen and then that random outcome will be left unchanged for long periods of time it does not dominate all other outcomes but is retained merely because of its particular history there are already several possible explanations for the observed stability in the literature we will take them up as they become relevant to the general line of reasoning i should however warn the reader that my own previous work including joint work with buchanan will play a major role here this may simply reflect egotism but i think that some of the early work which is now partially forgotten can provide solutions for more modern problems much recent public choice work has involved spatial models and these models frequently ignore logrolling the reason presumably is that it is very hard to put logrolling in a two dimensional diagram we shall begin considering such special models and assume that the issues are the sort that does not lead to logrolling and then turn to more complex logrolling problems with respect to the first situation in which logrolling does not occur there is already one possible explanation for the observed stability in the literature

the effects of agricultural development policies on income distribution and technological change in agriculture abstract a framework for analyzing the effects of policies on income distribution is introduced for the case where farmers have both discrete adoption decisions relating to fixed cost and continuous adoption decisions relating to land allocation distributional effects depend on the underlying distributions of farm size risk preferences and credit availability absolute and relative equity effects of various policies are shown to depend critically on which of these factors are major barriers to adoption and on the stochastic relationship of returns to various cropping activities a fixed cost subsidy appears to be a dominant policy from an equity standpoint in most cases

bilateral matching and bargaining with private information we study equilibria of a dynamic matching and bargaining game dmbg with two sided private information bilateral bargaining the model is a private information replica of mortensen and wright 2002 there are two kinds of frictions time

the diffusion of new agricultural technologies the case of crossbred cow technology in tanzania the recent literature on agricultural technology adoption shows that diffusion of new technologies varies significantly across space and time furthermore puzzles exist about why some seemingly profitable technologies are not adopted especially in livestock production we employ a hazard or duration function to explain diffusion of crossbred cow technology in a unique sample of tanzania farmers a farmer s adoption of crossbred technology depends positively on the proximity of his farm to other users on his schooling and on his access to credit and contact with extension agents

did the thai rice pledging programme improve the economic performance and viability of rice farming abstractthis article evaluates impacts of the rice pledging programme on the economic performance and viability of rice farming in thailand it also investigates whether the effects of the programme are heterogeneous across different farm types using the propensity score matching technique to address the self selection bias in the farm level data set we found that the programme enhanced the economic performance less than hoped for overall the programme was estimated to improve the net direct farm income for participating farms by 175 12 194 82 per hectare taking into account the heterogeneous effects of the programme across farm types we calculated that the greatest effects may be realized by farmers within the small farms subsample at 404 41 439 85 per hectare but only 139 80 213 36 per hectare for midsize farms and 138 82 173 34 per hectare for large farms with regard to the economic viability of the programme we discovered that it had an insignificant effect on farm modernization inve

rational bandits plunder public goods and the vikings the paper applies and extendsinsights from mancur olson s study of statemaking to the vikings in a world ofroving bandits a sub optimal provision ofpublic goods exists most notably ofsecurity roving banditry leads toover plundering and zero profits for theplunderers which makes stationary banditryprofitable the most efficient banditsmonopolize violence begin to tax andprovide some amounts of public goods inorder to stimulate economic growth theanalysis demonstrates how the vikings activities and settlements are consistentwith such an explanation with the dynamicsof the process being reflected in thevariation in the number of raids and theamount of wealth extracted

the constitutional economics of autocratic succession the paper extends and empirically tests gordontullock s public choice theory of the nature of autocracy a simple model of the relationship between constitutional rules governing succession in autocratic regimes and the occurrence of coups against autocrats is sketched the model is applied to a case study of coups against monarchs in denmark in the period ca 935 1849 a clear connection is found between the specific constitutional rules governing succession and the frequency of coups specifically the introduction of automatic hereditary succession inan autocracy provides stability and limits the number of coups conducted by contenders

strategic gerontocracy why nondemocratic systems produce older leaders one characteristic of nondemocratic regimes is that leaders cannot be removed from office by legal means in most authoritarian regimes no institutional way of dismissing incompetent rulers is available and overthrowing them is costly anticipating this people who have a say in the selection of the leader are likely to resort to alternative strategies to limit his tenure in this paper we examine empirically the strategic gerontocracy hypothesis because selecting aging leaders is a convenient way of reducing their expected time in office gerontocracy will become a likely outcome whenever leaders are expected to rule for life we test this hypothesis using data on political leaders for the period from 1960 to 2008 and find that dictators have shorter life expectancies than democrats at the time they take office we also observe variations in the life expectancies of dictators those who are selected by consent are on average closer to death than those who seize power in an irregular manner this finding suggests that gerontocracy is a consequence of the choice process since it disappears when dictators self select into leadership positions

learning from trades i study stationary cut off strategy equilibria of a dynamic market model where buyers sample sellers sequentially from an unknown distribution buyers learn about the distribution from the sampled sellers and a trade signal the trade signal reveals whether a randomly chosen seller traded yesterday observing a trade as opposed to no trade is good news about the distribution buyers who observe a trade use a higher cut off than buyers who observe no trade despite buyers learning from sampled sellers that puts a countervailing pressure on the cut offs the trade signal may reduce market efficiency while an appropriate exogenous signal increases efficiency

asymmetric information in bilateral trade and in markets an inversion result abstract i consider bilateral trade between a seller and a buyer with private valuations the seller makes a take it or leave it price offer if the seller observes the buyer s valuation symmetric information bilateral trade is trivially efficient if the seller cannot observe the valuation asymmetric information bilateral trade is inefficient this bilateral trading game is embedded into a large matching market in the steady state equilibrium of the market game the relation between the informational regime and efficiency is inverted with small frictions efficiency obtains if information is asymmetric if information is symmetric however the trading outcome can be very inefficient even if frictions vanish