bidding behavior in first price sealed bid auctions use of computerized nash competitors abstract results are reported from a series of first price sealed bid auctions where bidders face computerized nash equilibrium competitors the results provide strong support for employing this newly developed methodology as a testing procedure for nash equilibrium bidding models

theory and behavior of multiple unit discriminative auctions this paper reports the results of controlled experiments designed to test the harrisraviv generalization of the vickrey theory of bidding in multiple unit discriminative auctions the paper also discusses further development of the theory in a way suggested by the experimental results to include bidders with distinct risk preferences in a well known paper vickrey 20 formulated a nash equilibrium model of bidding by risk neutral economic agents in single unit auctions this analysis was subsequently extended in numerous papers vickrey 21 generalized his original model to include multiple unit auctions in which each of n risk neutral bidders can bid on one out of a total of q homogeneous items up for auction where 1 c q n in both of the vickrey papers individual values for the auctioned object s were assumed to be drawn from a uniform distribution holt 12 and riley and samuelson 19 for single unit auctions and harris and raviv 11 for multiple unit auctions have extended the vickrey model to the case in which valuations are from a general distribution function and all agents have identical concave utility functions this paper reports the empirical properties of individual bidding behavior and seller revenue for a group of 28 laboratory experiments designed to test the harris raviv generalization of the vickrey hereafter vhr model of nash equilibrium behavior in multiple unit discriminative auctions in section i we summarize briefly the theoretical results of the vhr model which form the basis for the hypotheses that we test section ii describes the experimental design that we use section iii describes the experimental results and various tests based on the bidding behavior of individual subjects and on aggregate market seller revenue data the results from six of the ten n q parameter designs reported

input subsidy programs in sub saharan africa a synthesis of recent evidence input subsidy programs have once again become a major plank of agricultural development strategies in africa ten african governments spend roughly us 1 billion annually on input subsidy programs isps amounting to 28 6 of their public expenditures on agriculture this article reviews the microlevel evidence on isps undertaken since the mid 2000s we examine the characteristics of subsidy beneficiaries crop response rates to fertilizer application and their influence on the performance of subsidy programs the impacts of subsidy programs on national fertilizer use and the development of commercial input distribution systems and finally the impact of isps on food price levels and poverty rates the weight of the evidence indicates that the costs of the programs generally outweigh their benefits findings from other developing areas with a higher proportion of crop area under irrigation and with lower fertilizer prices factors that should provide higher returns to fertilizer subsidies than in africa indicate that at least a partial reallocation of expenditures from fertilizer subsidies to r d and infrastructure would provide higher returns to agricultural growth and poverty reduction however because isps enable governments to demonstrate tangible support to constituents they are likely to remain on the african landscape for the foreseeable future hence the study identifies ways in which benefits can be enhanced through changes in implementation modalities and complementary investments within a holistic agricultural intensification strategy among the most important of these are efforts to reduce the crowding out of commercial fertilizer distribution systems and programs to improve soil fertility to enable farmers to use fertilizer more efficiently the challenges associated with achieving these gains are likely to be formidable

a test that discriminates between two models of the dutch first auction non isomorphism abstract previous experiments reject the hypothesis that the dutch and first auctions are isomorphic two alternatives to the standard normal form analysis of the dutch auction are formalized 1 bidders violate bayes rule 2 bidders experience a utility of suspense that is additive with the utility of monetary reward paired comparisons of bidding behavior between groups in which the treatment is to triple the payoff of the baseline group yields no significant effect of this treatment we therefore reject the utility of suspense model

information disclosure in auctions an experiment we report experimental results on the importance of information disclosure policy in first price sealed bid auctions interaction takes place in 10 periods according to a random matching protocol and we control the level of information feedback bidders receive after each period when bidders are informed about the losing bids in previous periods prices are higher than the theoretical prediction however when this information is not revealed the bidding becomes more competitive and the bids come close to the theoretical prediction we suggest that a signaling phenomenon may be important for explaining these results 2002 elsevier science b v all rights reserved

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

independent private value auctions bidder behaviour in first second and third price auctions with varying numbers of bidders the symmetric equilibrium of third price auctions is characterized it makes a number of contrasting predictions relative to firms and second price auctions bids exceed private values the marginal effects on bids of an increase in private values is greater than one increasing numbers of bidders reduces bids and risk aversion requires bidding below the risk neutral nash equilibrium in the experiment bidders do not always satisfy the point predictions of the theory however the game theoretic models correctly anticipate at least directionally the important effects of the price rule changes copyright 1993 by royal economic society

the last mile s in modern input distribution pricing profitability and adoption increasing adoption of modern inputs remains one of the best hopes for greater agricultural production in developing countries based on unique data from northwestern ethiopia this study examines the last mile s from the input distribution center to the farmer in the chemical fertilizer and improved seed distribution system we find that increasing transaction and transportation costs over a 35 km distance along a route mainly accessible to only foot traffic lead to a 50 increase of the price of chemical fertilizer and to a 75 reduction in its use farmers who live about 10 km from the distribution center face per unit transaction and transportation costs as high as the costs needed to bring the fertilizer from the international port to the input distribution center about 1 000 km tackling the last mile s costs should thus be a priority to improve modern input adoption and use in these settings

payments for ecosystem services and agricultural intensification evidence from a choice experiment on deforestation in zambia agriculture is considered to be one of the major drivers of deforestation worldwide in developing countries in particular this process is driven by small scale agriculture at the same time many african governments aim to increase agricultural productivity empirical evidence suggests however that win win relationships between agricultural intensification and forest conservation are the exception payments for ecosystem services pes could be linked to agriculture support programmes to simultaneously achieve both goals due to potentially higher profits from intensified agriculture than from pure cash transfers potential payment recipients may prefer in kind over conventional cash payments nevertheless little scientific evidence exists regarding the preferences of potential pes recipients for such instruments we report from a discrete choice experiment in zambia that elicited preferences of smallholder farmers for pes contracts our results suggest that potential pes recipients in zambia value in kind agricultural inputs more highly than cash payments even when the monetary value of the inputs is lower than the cash payment highlighting that pes could potentially succeed in conserving forests and intensifying smallholder agriculture respondents who intended to clear forest within the next three years were found to require higher payments but could be motivated to enrol in appropriately designed pes

5 information impact and allocation rules in auctions with affiliated private values a laboratory study in affiliated private value auctions each bidder has perfect information regarding his her own value for the object at auction but higher values of the item for one bidder make higher values for other bidders more likely we report on a series of experiments examining three key implications of these auctions i in a first price auction public information about rivals values increases expected revenue ii an english auction increases expected revenue compared to a first price auction and iii a second price auction is isomorphic to an english auction in examining these issues we compare predictions of some ad hoc bidding models with nash equilibrium predictions in the first price auction experiments nash equilibrium bidding theory organizes the data better than either of two ad hoc bidding models public information about others valuations does increase average revenue but the increase in revenue is smaller and less reliable than predicted under risk neutral nash equilibrium bidding lower average revenue might be attributed to risk aversion while the high variability is attributed to a sizable frequency of individual bidding errors relative to the theory bidding theory precisely organizes english auction outcomes after a brief initial learning period the dominant strategy equilibrium does not organize second price auctions nearly as well as market prices persistently exceed predicted prices the difference between english and second price outcomes is attributed to effects of different information flows inherent in the structure of the two institutions on eliminating bidding errors revenue impacts of these two institutions relative to a first price auction are examined in light of observed bidding patterns

factors influencing the profitability of fertilizer use on maize in zambia major findings the additional maize produced from a given amount of fertilizer applied varied widely across households even after largely controlling for soil and rainfall conditions the median estimated response rate was 15 9kgs of maize per kg nitrogen applied under the range of conditions and smallholder management practices average maizefertilizer response rates declined as the application rate increased beyond 2 bags of urea and 2 bags of d compound factors raising the response rate and profitability of fertilizer use included timely availability application rates less than the moa 4x4 recommendation use of animal draft power in land preparation and use of hybrid seed in remote areas and given current management practices fertilizer use appears to be profitable only for a minority of smallholder farmers in the relatively remote areas for farmers in the more accessible areas profitability of fertilizer use depends on timely availability if fertilizer is not available on time even farmers in the more accessible parts of this area of relatively high agronomic suitability for maize production are largely unable to use fertilizer profitably because over 30 percent of the households reported that fertilizer was delivered late these findings indicate that efforts to ensure timely distribution can contribute substantially to the productivity gains achievable from fertilizer use

tests of a heterogeneous bidders theory of first price auctions abstract this paper reports the results of eight first price sealed bid auction market experiments using cash motivated subjects to test a constant relative risk averse model crram of equilibrium bidding behavior of heterogeneous bidders

price formation in single call markets this paper reports a laboratory experiment designed to examine the price formation process in a simple market institution the single call market the experiment features random values and costs each period so each period generates a new price formation observation other design features are intended to enhance the predictive power of the bayesian nash equilibrium bne theory developed recently for this trading institution we find that the data support several qualitative implications of the bne but that subjects bid and ask behavior is not as responsive to changes in the pricing rule as the bne predictions bids and asks tend to reveal more of the underlying values and costs than predicted particularly when subjects are experienced nevertheless observed trading efficiency falls below the bne prediction the results offer more support for the bne when subjects compete against nash robot opponents a simple learning model accounts for several of the deviations from bne

simple econometrics of pesticide productivity this paper develops a multioutput generalization of the lichtenberg zilberman damage control technology the dual representation of the technology is shown to be conditionally additive in the price of abatement activities and other prices an econometric procedure for estimating the dual technology is developed and applied to an aggregate u s agricultural data set the conditionally additive nature of the model allows estimation of pest damage from the dual technology our estimates of aggregate u s pest damage are much lower than previous estimates

information and conspiracy in sealed bid auctions abstract this paper examines the allocative properties of the sealed bid institution when different aspects of the available information to bidders are considered specifically we examine a the effect on price determination in repeated sealed bid auctions of post auction revelation of losing bids and b the effect on price determination when conspiratorial discussions are allowed

market concentration and pricing behavior in the fertilizer industry a global approach the global fertilizer industry is a market with high and increasing levels of concentration and trade low income regions such as sub saharan africa are highly dependent on imported fertilizer and the landed price of imports at the port of entry usually represents a large fraction of the fertilizer supply costs in these regions this article formally examines the relationship between market concentration and prices from a global perspective we follow a dynamic panel approach using annual data on urea for a panel of countries and observe that prices are generally higher in more concentrated markets using different measures of concentration and model specifications based on additional simulations we find that a 10 increase in competition could increase fertilizer use by 13 19 and rural incomes by 1 2 in regions like sub saharan africa overall the results highlight the need to further examine the pricing behavior and potential market power exertion of major global producers which can help to better understand the industry supply chain in developing countries and provide additional insights into the design of policies including input subsidy programs intended to promote long term fertilizer adoption

theory and misbehavior of first price auctions comment glenn harrison s recent 1989 article in this review has provoked the loudest debate yet heard among experimental economists his critique of the james cox vernon smith and james walker 1983a b 1985a b 1988 henceforth csw laboratory studies of first price sealed bid auctions with independent and private values in my view raises a fundamental methodological issue that is well worth debating and the csw research program deserves further discussion in this short comment i confine myself to what i see as the most important issues and do not try to address all evidence relevant to the ongoing debate first i summarize harrison s central argument very briefly after pointing out two shortcomings in harrison s specific analysis of csw i propose a methodological reconciliation finally and with some trepidation since my own experience with the auction data is relatively slight i suggest an alternative approach to understanding the anomalies discovered by csw

rewards experience and decision costs in first price auctions consistent with a model of asymmetric risk aversion subjects in first price auctions consistently bid above the risk neutral nash prediction it has been argued that this is due to low opportunity cost of deviating from the risk neutral bid we increase opportunity cost and payoff levels by factors of 0 1 5 10 and 20 from the normal levels generating payoffs up to 250 for risk neutral subjects and observe an insignificant increase in the slope of individual bid functions the rmse of bids declines significantly this is consistent with a reward decision cost model of bidding behavior

integrating agronomic principles into production function specification a dichotomy of growth inputs and facilitating inputs this article presents a general conceptual framework for integrating agronomic principles into economic production analysis we categorize inputs in crop production into growth inputs and facilitating inputs based on this dichotomy we specify an asymmetric production function the robustness of the asymmetric framework is tested using crop level panel data on potato production in the netherlands the test results do not reject the proposed framework and the asymmetric specification better represents the underlying production technology

zambia s input subsidy programs over the last decade subsidies for fertilizer and hybrid maize seed have re emerged as a cornerstone of the government of the republic of zambia s grz s agricultural development and poverty reduction strategies this article reviews the farmer input support programme fisp and other grz input subsidy programs since structural adjustment it then synthesizes existing and presents new empirical evidence on the programs targeting outcomes and effects results suggest that although 73 of smallholder households cultivate less than 2 hectares of land and that these households constitute 78 of the smallholder farms below the us 1 25 capita day poverty line the majority 55 of fisp fertilizer goes to households that cultivate larger areas other factors constant wealthier households receive more subsidized inputs subsidized fertilizer promotes maize intensification and extensification at the expense of fallow land but an additional kg of subsidized fertilizer only raises maize output by 1 88 kg on average as a result of low maize fertilizer response rates poor targeting crowding out and diversion of fertilizer intended for the program financial benefit cost ratios for fisp fertilizer are well below one the article concludes with recommended reforms to fisp including that it be downsized and the savings invested in known drivers of pro poor agricultural growth

a nonparametric approach to the von liebig paris technology we develop the dual implications of the von liebig paris nutrient response technology and parametric and nonparametric tests for this technology we discuss the nonparametric approach using two different representations corresponding to optimistic and pessimistic nonparametric approximations of the technology application of the nonparametric approach to two experimental data sets and to two data sets generated by monte carlo methods confirms the presence of yield plateaus but provides mixed evidence regarding input nonsubstitution the optimistic representation exhibits virtually no input substitution while the pessimistic representation shows considerable substitutability

sifting through the weeds understanding heterogeneity in fertilizer and labor response in central malawi abstract despite heavy subsidies provided by the malawian government input use remains low estimated maize response rates to fertilizer vary widely across studies raising questions about the sources of this variability and whether fertilizer is generally profitable for most smallholder farmers at commercial prices this study uses survey and soil data from farmer identified most and least fertile maize plots in central malawi to explain the heterogeneity in maize response to inputs and to determine whether this heterogeneity explains low uptake of commercial fertilizer we estimate maize yield functions to characterize the range of maize response to fertilizer and weeding labor at locations that vary from marginal to mesic environments and show that differences in productivity persist with a plot level fixed effect and are not solely attributable to farmer skill using a range of price scenarios and classifying soil fertility by total organic carbon levels we find that fertilizer is more profitable on low fertility plots while current levels of weeding labor are more likely to be profitable on the high fertility plots the largest variation in profitability occurs between plots rather than price scenarios highlighting the importance of policies to improve soil fertility and address constraints to use of complementary inputs

an analysis of the impact of sample attrition on the second generation of respondents in the michigan panel study of income dynamics only a few studies have tried to estimate the trend in the elasticity of children s economic status with respect to parents economic status and these studies produce conflicting results in an attempt to reconcile these findings we use the panel study

is increasing inorganic fertilizer use for maize production in ssa a profitable proposition evidence from nigeria inorganic fertilizer use across sub saharan africa is generally considered to be low yet the notion that fertilizer use is too low is predicated on the assumption that it is profitable to use rates higher than currently observed there is however limited empirical evidence to support this using a nationally representative panel dataset this paper empirically estimates the profitability of fertilizer use for maize production in nigeria we find that fertilizer use in nigeria is not as low as conventional wisdom suggests low marginal physical product and high transportation costs significantly reduce the profitability of fertilizer use apart from reduced transportation costs other constraints such as soil quality timely access to the product and availability of complementary inputs such as improved seeds irrigation and credit as well as good management practices are also necessary for sustained agricultural productivity improvements

the theory of contracts and agency there has been much work recently on the effects of informational asymmetries on allocation and economic welfare these asymmetries render complete contracting infeasible or at least unenforceable and the resulting inefficiency creates incentives for information gathering various kinds of contracts emerge from the interaction of these incentives with the costs of contracting in this survey we shall attempt a brief critical review of the contracts literature point out some open questions and suggest some directions for future research section two discusses how moral hazard problems are solved in simple principal agent models section three considers adverse selection problems the fourth section discusses the form of contracts that arise in response to the above problems in labor markets finally in the last section we consider some recent developments and open questions

theory and misbehavior in first price auctions comment in his recent paper in this review glenn harrison 1989 argues that the conclusions of james cox et al 1982 1983 1985 1988 in their studies of first price private value auctions are not well supported because of shortcomings in the way their experimental investigations were designed analyzed and reported harrison argues that the expected cost of deviations from risk neutral nash equilibrium rnne bidding in these auctions was quite small less than 0 05 at the median so that in terms of expected monetary payoffs payoff space many subjects had little to lose from deviating from the rnne strategy harrison suggests that the significance of the differences cox vernon smith and james walker hereafter csw report between subjects bids and the rnne bids deviations in the message space may therefore need to be reexamined in discussing harrison versus csw we have three primary points to make first in arguing that it is more natural to evaluate subject behavior in expected payoff space harrison 1989 p 749 we think harrison has overstated his case however we agree with his more important point that looking at the cost of deviations is a useful diagnostic tool for determining when experimenters are likely to have lost control over subjects incentives further as we will show in section i this part of harrison s critique applies with special force to csw s studies of bidding second a broader examination of the results of private value auction experiments indicates that risk aversion cannot be the only factor and may well not be the most important factor behind bidding above the rnne found so often in first price privatevalue auctions the most telling evidence here is bidding above the dominant bid price found in second price auctions kagel et al 1987 kagel and levin 1990 and the risk loving found under several treatment conditions in csw s 1984 own multipleunit discriminative auctions auctions in which the high bidders pay their bid price these and other data inconsistent with risk averse bidding are largely ignored in csw 1988 but are nevertheless relevant to the substantive issue of risk aversion in private value auctions they are discussed in section ii third there are data gathered in other investigations which provide strong support for the view that the deviations from rnne bidding reported in first price auctions are not the results of the low expected cost of such deviations however these data unlike the higher stakes payoff data that csw offer in response to harrison are not consistent with csw s subsidiary conclusions that the data can be well accounted for by a narrow class of risk aversion parameters for the bidders together with the assumption that all agents are playing a nash equilibrium of the resulting game of incomplete information a key difference between these experiments and csw s is that if subjects do not respond to csw s treatment condition increasing the payoffs from experimental to u s dollars their behavior will be consistent with csw s theory in contrast department of economics university of pittsburgh pittsburgh pa 15260 we thank jack ochs and emilie roth for thoughtful discussions on earlier drafts of the paper jim cox and glenn harrison for helpful comments on the initial draft of the paper susan garvin for research assistance and ray battalio carl kogut and don meyer for providing us with access to their data research support was provided by the information science and technology and economics divisions of the national science foundation the alfred p sloan foundation and the russell sage foundation the usual caveat applies with special force iwe do not respond to specific comments that csw 1992 make in response to our comment as in order to avoid indefinite regress the ground rules for this debate required us to comment on csw s criticism of harrison after which they would be given the opportunity to respond to our comment

nonlinear behavior in sealed bid first price auctions the extent to which the behavior of people is consistent with game theoretic principles is investigated in a first price sealed bid auction environment three linear rules of thumb with increasing complexity are used as benchmarks to gauge the accuracy of the constant relative risk aversion model crram in addition the crram is tested against the relaxation of the rational expectation hypothesis existing competitive bidding experiments cannot clearly distinguish between game theoretic models and linear markdown rules on an individual level within the parametric environments studied and reported in the experimental literature game theoretic solutions are linear over the range of private values in which bid functions are estimated in this study agents drew values from non uniform distributions as a result the game theoretic bidding behavior is nonlinear due to the nonlinearity special econometric and numerical techniques are applied to solve the model and obtain the estimates the crram exhibits good fit of the data the pseudo r2 is greater than 0 8 in 90 percent of the subjects the crram is more accurate than the markdown model mm and the simple ad hoc model simam but not as accurate as the sophisticated ad hoc model sop am the data also supports the relaxation of the rational expectation hypothesis and suggests that substantial increases in the predictive power of game theoretic models can be gained from improvements in the theory of belief formation

individual behavior of first price auctions the importance of information feedback in computerized experimental markets abstract this article reports the results of an individual choice experiment designed to test the nash equilibrium predictions of the first price sealed bid auction a subject faced in 100 auctions always the same resale value and competed with computer simulated bids the design used between subjects variation and involved information feedback as the treatment variable earlier experimental work on first price auctions has frequently reported an overbidding relative to the risk neutral nash equilibrium our data provide evidence that overbidding can be fostered by the standard information feedback in auction experiments which after each auction reveals the winning bid only by means of learning direction theory we explain the individual bidding dynamics in our experiment finally we apply impulse balance theory and make long run predictions of individual bidding behavior

experimental development of sealed bid auction theory calibrating controls for risk aversion we offer a brief survey of bidding theory in high price auctions of experimental studies of behavior in such auctions and of the interplay between the design and results of the experiments and efforts to further develop the theory two new series of experiments are reported the first applies a convex transformation of payoffs in an attempt to induce a lowering of subject bids as if the bidders had become less risk averse the second applies a method for inducing any prespecified utility function for risky choices on an individual we use it to induce as if risk neutral behavior both series use baseline control to calibrate the hypothesized effect of the procedures on riskaverse behavior

the panel study of income dynamics after fourteen years an evaluation this article considers the representativeness of the panel study of income dynamics psid over its 14 year history from 1968 to 1981 given the dynamics of entry and exit from the panel by 1981 40 of the original members had left the sample and were replaced by new entrants who joined either existing households or new households being formed by members of the original sample we consider the distribution of demographic characteristics and earnings equations over time and we compare the psid with the current population survey cps by either approach we find little evidence that the psid has become unrepresentative

input use and market development in sub saharan africa an overview abstract this paper sets forth the background and objectives of this special issue trends in input use since 1980 are reviewed and a conceptual framework is presented for analyzing problems of input use and formulating strategies for resolving them reasons for low levels of fertilizer use by smallholder farmers are summarized briefly the essential points of the papers in the special issue and their implications for further expansion of input use in sub saharan africa are then outlined

resolving uncertainty about the number of bidders in independent private value auctions an experimental analysis results from first price sealed bid auctions in which there is uncertainty regarding the number of bidders are reported consistent with recent theoretical findings concealing information regarding the number of bidders raises more revenue for the seller than revealing information individual bids show that 1 narrowly interpreted the nash equilibrium bidding theory underlying these theoretical predictions is rejected as less than 50 of all bids satisfy the strict inequality requirements of the theory but 2 a majority of the deviations from these inequality requirements favor the revenue raising predictions of the nash model and in a large number of cases involve marginal violations of the theory

impulse balance equilibrium and feedback in first price auctions abstract experimental sealed bid first price auctions with private values in which feedback on the losing bids is provided yield lower revenues than auctions where this feedback is not given the concept of weighted impulse balance equilibrium which is based on a principle of ex post rationality and incorporates a concern for social comparison captures the data

an analysis of sample attrition in panel data the michigan panel study of income dynamics by 1989 the michigan panel study on income dynamics psid had experienced approximately 50 percent sample loss from cumulative attrition from its initial 1968 membership we study the effect of this attrition on the unconditional distributions of several socioeconomic variables and on the estimates of several sets of regression coefficients we provide a statistical framework for conducting tests for attrition bias that draws a sharp distinction between selection on unobservables and on observables and that shows that weighted least squares can generate consistent parameter estimates when selection is based on observables even when they are endogenous our empirical analysis shows that attrition is highly selective and is concentrated among lower socioeconomic status individuals we also show that attrition is concentrated among those with more unstable earnings marriage and migration histories nevertheless we find that these variables explain very little of the attrition in the sample and that the selection that occurs is moderated by regression to the mean effects from selection on transitory components that fade over time consequently despite the large amount of attrition we find no strong evidence that attrition has seriously distorted the representativeness of the psid through 1989 and considerable evidence that its cross sectional representativeness has remained roughly intact

rejoinder to the comment by andrew dorward and ephraim chirwa on jayne t s d mather n mason and j ricker gilbert 2013 how do fertilizer subsidy program affect total fertilizer use in sub saharan africa crowding out diversion and benefit cost assessments agricultural economics 44 6 687 703

are kenyan farmers under utilizing fertilizer implications for input intensification strategies and research abstract it is widely perceived that african farmers are under utilizing inorganic fertilizer however very little long term evidence from farmers fields accounting for variations in agro ecological conditions has been assembled to back this claim or determine the conditions under which it is true using five waves of nationwide household survey data from kenya covering 13 years we estimate the relative and absolute profitability of nitrogen application rates on maize fields and compare these profitability conditions to observed nitrogen use patterns over time in general we find that farmers are consistently and steadily increasing towards risk adjusted economically optimal rates of fertilizer application over time and that in the most agriculturally productive areas farmers application rates on maize sometimes exceed rates that maximize profitability fertilizer use rates may nevertheless be profitably raised in these areas but doing so will require the adoption of complementary inputs and management practices that raise maize response rates to fertilizer application this motivates a more holistic approach to input intensification strategies in the region

risk attitudes in first price auction experiments a bayesian analysis non cooperative bidding theory for sealed bid auctions generally implies testable predictions that are conditioned on the risk attitudes of agents received laboratory experiments that purport to test this theory do not generally control for the risk attitudes of subjects those experiments exhibit behavior inconsistent with popular bidding models that assume that agents have the same aversion to risk or are all risk neutral this paper constructs an explicit bayesian prior distribution for the risk attitudes of experimental subjects and reconsiders the experimental results it finds that observed bidding behavior is still inconsistent with the nash predictions when explicit prior weights are attached to alternative assumptions about subject risk attitudes thus one cannot account for observed bidding anomalies by appealing to uncontrolled nuisance variables such as risk attitudes non cooperative bidding theory for sealed bid auctions generally implies testable predictions that are conditioned on the risk attitudes of agents archetypical of this result is the nash equilibrium prediction for first price auctions for an object that is valued by agents in an independent and private manner received laboratory experiments that purport to test this theory do not generally control for the risk attitudes of subjects those experiments exhibit behavior inconsistent with popular bidding models that assume that agents have the same aversion to riskor are all risk neutral in this paper we construct an explicit prior distrlbution for the risk attitudes of experimental subjects and reconsider the experimental results we find that observed bidding behavior is indeed consistent with the nash predictions when explicit prior weights are attached to alternative assumptions about subject risk aversion however when one allows for risk loving subjects as well observed behavior is inconsistent with nash predictions thus one cannot account for observed bidding anomalies by appealing to uncontrolled nuisance variables such as risk attitudes in section i we consider a specific nash equilibrium ne bidding model due to cox roberson and smith 1982 and cox smith and walker 1988 that clearly illustrates the risk sensitivity of the theoretical predictions in section ii we provide independent evidence of the risk attitudes of experimental subjects in a test for risk attitudes developed by harrison 1986a this evidence allows us to construct an explicit prior probability density function over the coefficient of constant relative risk attitudes employed in the specific bidding model of section i in section iii we reconsider the evidence from the first price fp experiments reported in cox roberson and smith 1982 and cox smith and walker 1983a 1983b i a specific bidding model cox roberson and smith 1982 hereafter crs present a model based on a power function utility specification for agent i ui y y 1 received for publication august 31 1987 revision accepted for publication december 18 1989 university of south carolina i am grateful to two anonymous referees for helpful comments although they are not responsible for my conclusions

the complex dynamics of smallholder technology adoption the case of sri in madagascar this article explores the dynamics of smallholder technology adoption with particular reference to a high yielding low external input rice production method in madagascar we present a simple model of technology adoption by farm households in an environment of incomplete financial and land markets we then use a probit model and symmetrically censored least squares estimation of a dynamic tobit model to analyze the decisions to adopt expand and disadopt the method we find that seasonal liquidity constraints discourage adoption by poorer farmers learning effects both from extension agents and from other farmers exert significant influence over adoption decisions

factors explaining the low and variable profitability of fertilizer application to maize in zambia it is widely recognized that an african green revolution will require greater use of inorganic fertilizers often made comparisons note that fertilizer use rates in africa are just 10 20 of those in asia europe and the americas most attempts to explain relatively low adoption of fertilizer assume yield responses to inorganic fertilization warrant higher application rates and hypothesize that observed use rates are limited by market based factors another explanation may be that application rates are low because african yields are less responsive to inorganic fertilizer than yields in other regions and less responsive than analysts perceive examining the case of zambia we evaluate whether yield response to fertilizers could explain adoption and application rates a model of yield response is constructed and a combination of estimators is employed to mitigate potential biases related to correlation between fertilizer use and unobserved heterogeneity as well as stochastic shocks results indicate higher fertilization rates would be marginally profitable or unprofitable in many cases given commercial fertilizer and maize prices phosphoric fertilizer is particularly unprofitable on acidic soils which are common in zambia and other areas of sub saharan africa we propose feasible recommendations for diversifying the current government strategy to enhance crop productivity

theory and misbehavior of first price auctions recent experimental evidence appears to reject simple nash equilibrium models of bidding behavior in first price auctions the author presents a methodological critique of this evidence existing tests have concentrated on deviations of subjects from predictions in the message space of the action bid deviations the author suggests that it is more natural to evaluate subject behavior in expected payoff space he concludes that the evidence against the simple models is not significant enough to warrant their rejection copyright 1989 by american economic association