complex dynamics in a cobweb model with adaptive production adjustment abstract chaos occurs in a nonlinear cobweb model with normal demand and supply naive expectations and adaptive production adjustment the model differs from existing ones in that it includes adaptive production adjustment instead of adaptive expectations the model exhibits observable chaos strange attractors as well as topological chaos horseshoes associated with homoclinic points as numerical simulations show the faster suppliers adjust their production and the more inelastic demand is the more likely the market behaves chaotically

multiproduct short run hospital cost functions empirical evidence and policy implications from cross section data economists and policymakers have been interested in hospital costs and the structure of hospital technologies for several decades now early interest was focused on the possibility of scale economies which implied increased efficiency for larger hospitals 6 8 12 13 18 20 while more recent interest has been stimulated by the inflationary spiral of hospital costs 1 15 17 22 as hospital costs have risen important policy questions concerning the impact on costs of the hospitals diagnostic case mix the hospitals admitting physicians the hospitals size and the hospitals efficiency have emerged and researchers have attempted to deal with these issues within the context of increasingly complex econometric models 1 2 5 24 27 however in attempting to analyze these important policy issues researchers have been forced to make two major types of compromises on the one hand appropriate data are often not available for estimating a well specified cost function e g information on admitting physicians and diagnostic case mix are often missing so that problems of specification error often plague the econometric results conversely in using imaginative ways to deal with data problems e g weighting in patient and out patient care to form a single index of hospital services 1 27 or estimating separate cost functions for each department in the hospital 2 researchers sometimes place unrealistic and unnecessary constraints on their econometric models the purpose of this study is to analyze the impact of several of the primary hospital characteristics mentioned above on the short run costs of hospitals within a theoretically consistent framework in the following discussion we also develop the theoretical

artificial adaptive agents in economic theory economic analysis has largely avoided questions about the way in which economic agents make choices when confronted by a perpetually novel and evolving world as a result there are outstanding questions of great interest to economics in areas ranging from technological innovation to strategic learning in games this is so despite the importance of the questions because standard tools and formal models are ill tuned for answering such questions however recent advances in computer based modeling techniques and in the subdiscipline of artificial intelligence called machine learning offer new possibilities artificial adaptive agents aaa can be defined and can be tested in a wide variety of artificial worlds that evolve over extended periods of time the resulting complex adaptive systems can be examined both computationally and analytically offering new ways of experimenting with and theorizing about adaptive economic agents many economic systems can be classified as complex adaptive systems such a system is complex in a special sense i it consists of a network of interacting agents processes elements ii it exhibits a dynamic aggregate behavior that emerges from the individual activities of the agents and iii its aggregate behavior can be described without a detailed knowledge of the behavior of the individual agents an agent in such a system is adaptive if it satisfies an additional pair of criteria the actions of the agent in its environment can be assigned a value performance utility payoff fitness or the like and the agent behaves so as to increase this value over time a complex adaptive system then is a complex system containing adaptive agents networked so that the environment of each adaptive agent includes other agents in the system complex adaptive systems usually operate far from a global optimum or attractor such systems exhibit many levels of aggregation organization and interaction each level having its own time scale and characteristic behavior any given level can usually be described in terms of local niches that can be exploited by particular adaptations the niches are various so it is rare that any given agent can exploit all of them as rare as finding a universal competitor in a tropical forest moreover niches are continually created by new adaptations it is because of this ongoing evolution of the niches and the perpetual novelty that results that the system operates far from any global attractor improvements are always possible and indeed occur regularly the everexpanding range of technologies and products in an economy or the everimproving strategies in a game like chess provide familiar examples adaptive systems may settle down temporarily at a local optimum where performance is good in a comparative sense but they are usually uninteresting if they remain at that optimum for an extended period a theory of complex adaptive systems based on aaa makes possible the development of well defined yet flexible models that exhibit emergent behavior such models can capture a wide range of economic phenomena precisely even though the development of a general mathematical theory of complex adaptive systems is still in its early stages the aaa models complement current theoretical directions they are

costs and factor substitution in the provision of local fire services evidence on costs and factor substitution is presented for a sample of local fire departments in new york state the results suggest that fire service production does not fit either leontief cobb douglas or ces technology in addition exogenous socioeconomic variables are found to significantly affect public sector costs and the estimates of factor price elasticities the findings of relatively low factor demand and substitution elasticities suggest that local governments may have limited flexibility in adjusting their production of fire services to minimize the impact of rising factor prices copyright 1992 by mit press

congested public goods the case of fire protection abstract this paper uses a fire protection measure based on a community s fire insurance rating to estimate the strength of congestion effects for fire protection services the empirical results show that the congestion properties of fire protection are much like those of a pure public good in addition the paper introduces a new notion of returns to scale for public goods and estimates the relevant parameters for the fire protection case

simulating the effects of environmental and market variability on fishing industry structure abstract an agent based model comprising a fish stock a fishing fleet and a fish market is used to investigate the combined effects of environmental and market variability on the structure of a fishery over 15 year simulations agents make daily fishing decisions and annual entry exit and investment decisions based on the fishery s past economic outcomes and their individual risk preferences and opportunity costs e g an alternative source of income environmental variability is simulated through fishing success variability while market variability is simulated through changes in the elasticity of the demand curve i e the responsiveness of market prices to changes in daily landings our findings indicate that changes in variability lead to changes in economic and biological conditions of the fishery by influencing the composition of risk preferences within the fleet counter to expectations market stability did not dampen the negative impacts of environmental variability but rather stimulated over investment and increased harvesting by a small number of risk seeking fishers results from this research suggest that climate driven increases in fisheries variability coupled with increases in market integration that act to reduce local price signals may lead to inefficient investments and reduced fishery resources

regional growth linkages from agriculture pioneering research on downstream linkages from agriculture is said to demonstrate that consumption links rather than production links are the main source of indrect growth effects that these consumption links take the form of labour intensive goods and services produced locally and that the largest farm enterprises are most locally multiplicative of activities mopping up surplus rural labour this article has two purposes first the methodologies assumptions and data base for the quantification of the local and non local regional multiplier effects from agricultural development are examined second the contradictory interpretations for agricultural policy which have arisen from these exercises of quantification are discussed and an attempt made to explain their bases

measuring the impact of consumption linkages on the employment effects of mechanisation in philippine rice production a variant on the social accounting matrix method is used to measure consumption linkages of alternative rice production technologies the model is built for technology observed in the philippines consumption linkages are computed by incorporating consumption distribution and import substitution effects one essence of the input output framework is the recognition of multiple sub sectors for production of a single product rice simulations consider a one per cent change on consumer spending for rice met from one sub sector compared to another results indicate that the changes in employment that occur under different technological options depend importantly on the indirect effects arising from consumption linkages

equilibrium and reinforcement learning in private information games an experimental study abstract this paper examines the abilities of standard game theoretic solution concepts static nash equilibrium and a simple model of individual learning to describe subject behavior in an experiment involving private information games with mixed strategy nash equilibrium outcomes the experimental data are compared in several ways with the predictions of static nash equilibrium and the quite different predictions of the learning model which is based on the models of roth and erev 1995 games and economic behavior special issue nobel symposium vol 8 pp 164 212 nash equilibrium does not adequately describe subject behavior whereas the learning model performs well in describing aspects of the evolution in behavior over time

economies of size and scope in rural low volume roads evidence on cost savings from reorganizing township low volume rural road systems into larger units is presented in this study of technical efficiencies in producing local government services data is from a sample of midwestern townships heterogeneity of surface types is accounted for by specifying a multiple output translog cost function examination of economies of size suggests that cost savings could be realized by reorganizing townships into larger units the presence of economies of scope suggests that jurisdictions should not specialize in maintenance responsibilities due to the joint use of inputs

learning by imitation abstract this paper introduces a learning algorithm that allows for imitation in recursive dynamic games the kiyotaki wright model of money is a well known example of such decision environments in this context learning by experience has been studied before here we introduce imitation as an additional channel for learning in numerical simulations we observe that the presence of imitation either speeds up social convergence to the theoretical markov nash equilibrium or leads every agent of the same type to the same mode of suboptimal behavior we observe an increase in the probability of convergence to equilibrium as the incentives for optimal play become more pronounced

deep impact geo simulations as a policy toolkit for natural disasters adverse post natural disaster outcomes in low income regions like elevated internal migration levels and low consumption levels are the result of market failures poor mechanisms for stabilizing income and missing insurance markets which force the affected population to respond and adapt to the shock they face in a spatial environment with multiple locations with independent but inter connected markets these transitions quickly become complex and highly non linear due to the feedback loops between the micro individual level decisions and the meso location wise market decisions to capture these continuously evolving micro meso interactions this paper presents a spatially explicit bottom up agent based model to analyze natural disaster like shocks to low income regions the aim of the model is to temporally and spatially track how population distributions income and consumption levels evolve in order to identify low income workers that are food insecure the model is applied to the 2005 earthquake in northern pakistan which faced catastrophic losses and high levels of displacement in a short time span and with market disruptions resulted in high levels of food insecurity the model is calibrated to pre crisis trends and shocked using distance based output and labor loss functions to replicate the earthquake impact model results show how various factors like existing income and saving levels distance from the fault line and connectivity to other locations can give insights into the spatial and temporal emergence of vulnerabilities the simulation framework presented here leaps beyond existing modeling efforts which usually deals with macro long term loss estimates and allows policy makers to come up with informed short term policies in an environment where data is non existent policy response is time dependent and resources are limited

can neoclassical economics handle complexity the fallacy of the oil spot dynamic abstract this paper is essentially a rebuttal of the view that neoclassical economics can handle complexity i have coined the locution oil spot dynamic to denote the neoclassical ability to subsume each and every new perspective the main part of the paper is devoted to showing why the oil spot dynamic cannot work with the complexity approach which is seen as a coherent stand alone research program that stems from the sfi economics program and manifests itself with different nuances the fallacy of the oil spot dynamic is relevant in this period in which economists are beginning to realize that the neoclassical samuelsonian paradigm no longer represents the common language of their profession the spread of the complexity approach and the dissolving notion of mainstream are here interpreted as indicative of a changing economics a short foray into the features of the process of change completes my arguments by showing that the shift from one paradigm to another has many interrelated dimensions and that there may be rigidities internalizing changes

fire department demand and supply in large cities the purpose of this study is to estimate demand and production functions for fire fighters provided in major cities several factors including the level of fire losses in the communityper capitaincome relative wages of fire fighters population density city size and poverty are used in the analysis this study differs from earlier ones in two ways first multiple measures of community fire losses instead of the usual one are used in the analysis second in contrast with earlier studies of fire protection which have typically relied on ordinary least squares regression analysis ols to study either demand or production this study employs two stage least squares regression analysis 2sls to simultaneously estimate demand and production relations evidence is found that demand for fire fighting is affected by both fire losses and relative size of per capitaincome to fire fighter wages losses in turn are affected by fire fighting hours by poverty and by density there is some evidence for econo

information processing and bounded rationality a survey this paper surveys recent attempts to formulate a plausible and tractable model of bounded rationality the author focuses in particular on models that view bounded rationality as stemming from limited information processing he discusses partitional models such as computability automata perceptions and optimal networks nonpartitional models and axiomatic approaches

risk preference forecasting accuracy and survival dynamics simulations based on a multi asset agent based artificial stock market abstract the relevance of risk preference and forecasting accuracy to the survival of investors is an issue that has recently attracted a number of theoretical studies by using agent based computational modeling this paper extends the existing studies to an economy where adaptive behaviors are autonomous and complex heterogeneous specifically a computational multi asset artificial stock market corresponding to blume and easley blume l easley d 1992 evolution and market behavior journal of economic theory 58 9 40 and sandroni sandroni a 2000 do markets favor agents able to make accurate predictions econometrica 68 1303 1341 is constructed and studied through simulation we present results that contradict the market selection hypothesis

transformation of the rural economy in the philippines 1988 2006 abstract this research explores the changing structure of the rural economy in the philippines from 1988 to 2006 we found that the expansion and upgrade of infrastructure such as electricity and roads and investment in secondary and tertiary education are important factors that induced the economic transformation of the rural economy the importance of higher education as an entry requirement to the nonfarm labor market has declined over time indicating that the rural nonfarm sector has been increasingly providing employment opportunities to the unskilled and the uneducated who form the bulk of the rural poor

money as a medium of exchange in an economy with artificially intelligent agents abstract we study the exchange economies of kiyotaki and wright 1989 in which agents must use a commodity or fiat money as a medium of exchange if trade is to occur our agents are artificially intelligent and are modeled as using classifier systems to make decisions in the assignment of credit within the classifier systems we introduce some innovations designed to study sequential decision problems in a multi agent environment for most economies that we have simulated trading and consumption patterns converge to a stationary nash equilibrium even if agents start with random rules in economies with multiple equilibria the only equilibrium that emerges in our simulations is the one in which goods with low storage costs play the role of medium of exchange i e the fundamental equilibrium of kiyotaki and wright

farm mechanization in a semiclosed input output model the philippines employment and income distribution consequences of farm mechanization are estimated using a semiclosed input output model incorporating factor intensity consumption and import substitution effects rice production and agricultural machinery vectors from the national input output table are disaggregated into technology specific subsectors consumption is disaggregated into five household classes differing in consumption savings and imports simulations of a one percent change in consumer spending for rice met from one subsector compared to another indicate that indirect effects partially offset employment reduction from machinery and reinforce the employment increase from irrigation intensification furthermore irrigation is found to offset the inequitable effects of mechanization

genetic algorithm learning and the cobweb model this paper presents the cobweb model in which competitive firms in a market for a single good use a genetic algorithm to update their decision rules about next period production and sales the results of simulations show that the genetic algorithm converges to the rational expectations equilibrium for a wider range of parameter values than other algorithms frequently studied within the context of the cobweb model price and quantity patterns generated by the genetic algorithm are also compared to the data of experimental cobweb economies it is shown that the algorithm can capture several features of the experimental behavior of human subjects better than three other learning algorithms that are considered

an analysis of returns to scale in public production with an application to fire protection abstract this paper analyzes returns to scale in public production existing studies fail to differentiate among three dimensions of scale service quality the level of governmental activity and the number of people served a fourth dimension economies of scope is need for agencies that provide multiple services this paper provides a formal definition of returns to scale for each dimension this framework is applied to fire protection using a translog cost function with two services fire prevention and fire suppression the results indicate economies of scope increasing returns to quality scale and constant returns to population scale

the source of optimality in action it is well known that the nature of the information set and the axioms of rational choice are critical in determining the type of ranking on which agents are held to act in economic theory this paper argues that the concept of the optimising agent is also sensitive to the conception of the relation between a ranking of options facing an agent and concrete action what is termed the realisation process three conceptions of the realisation process are examined which are seen to lead to three quite distinct views on the role of agency the enabling conditions under which the concept of the optimising agent may be legitimately applied and the resulting domain of application of optimisation

beyond microfoundations towards a not too rational macroeconomics at ucla we are establishing a center for computable economics i have been very much involved in this effort this may surprise you that a non mathematical macro monetary economist should become an enthusiast for this project is one of those things that do not compute but then as i will explain we take a special interest in things that do not compute one may come to computable economics by many intellectual routes i will trace my own not because it makes a particularly edifying story but because it will tell you what kind of problems i hope we can make progress on by developing the field of computable economics but before we get to that i had better explain what i mean by computable economics

a learning to forecast experiment on the foreign exchange market with a classifier system abstract this paper reports on an experiment of learning and forecasting on the foreign exchange market by means of an artificial intelligence methodology a classifier system which simulates learning and adaptation in complex and changing environments the experiment has been run for two different exchange rates the us dollar d mark rate and the us dollar yen rate representative of two possibly different market environments a fictitious artificial agent is first trained on a monthly data base from 1973 to 1990 and then tested out of sample from 1990 to 1992 its forecasting performance is then compared with the performance of decision rules which follow the prescription of various economic theories on exchange rate behaviour and the performance of forecasts given by var estimations of the exchange rate s determinants

adaptive behavior and economic theory the relationship between psychological and economic views of behavior once a subject of heavy dispute is now understood in a very similar way by practitioners of both these disciplines and of our sister social sciences in general terms we view or model an individual as a collection of decision rules rules that dictate the action to be taken in given situations and a set of preferences used to evaluate the outcomes arising from particular situation action combinations these decision rules are continuously under review and revision new decision rules are tried and tested against experience and rules that produce desirable outcomes supplant those that do not i use the term adaptive to refer to this trial anderror process through which our modes of behavior are determined if one is interested in modeling particular decisions in any very explicit way it is obviously necessary to think about rather narrow aspects of an individual s entire set of decision rules his or her personality experimental psychology has traditionally focused on the adaptive process by which decision rules are replaced by others in this tradition the influence of the subject s or as an economist says the agent s preferences this essay uses a series of examples to illustrate the use of rationality and adaptation in economic theory it is argued that these hypotheses are complementary and that stability theories based on adaptive behavior may help to narrow the class of empirically interesting equilibria in certain economic models an experiment is proposed to test this idea

production of public safety are socioeconomic characteristics of local communities important factors this paper uses the translog cost function and cross section data from florida to investigate the importance of socioeconomic characteristics sec of local communities in the production of public safety the approach used is noteworthy in four respects 1 the underlying production function is specified as an agem production function 2 sec are treated as non purchased fixed inputs 3 two variables are used to proxy sec in estimation and 4 the paper test for the existence of endogenous quality differences in safety it is shown that exclusion of sec from the production cost function of safety leads to misspecification and hence they provide a misleading guide to policy

cross border electricity market effects due to price caps in an emission trading system an agent based approach the recent low co2 prices in the european union emission trading scheme eu ets have triggered a discussion whether the eu ets needs to be adjusted we study the effects of co2 price floors and a price ceiling on the dynamic investment pathway of two interlinked electricity markets loosely based on great britain which already has introduced a price floor and on central western europe using an agent based electricity market simulation with endogenous investment and a co2 market including banking we analyse the cross border effects of national policies as well as system wide policy options a common moderate co2 auction reserve price results in a more continuous decarbonisation pathway this reduces co2 price volatility and the occurrence of carbon shortage price periods as well as the average cost to consumers a price ceiling can shield consumers from extreme price shocks these price restrictions do not cause a large risk of an overall emissions overshoot in the long run a national price floor lowers the cost to consumers in the other zone the larger the zone with the price floor the stronger the effect price floors that are too high lead to inefficiencies in investment choices and to higher consumer costs

learning with misspecification in an artificial currency market abstract agents evolve their forecast rules over time via a modified genetic algorithm in a simple artificial currency market these forecast rules can be nonlinearly misspecified when the misspecification is suppressed learning tends to be complete when it is not suppressed learning can generate persistent exchange rate dynamics

the use of input output analysis to determine the appropriateness of technology and industries evidence from bangladesh since the proportion of available capital to labor is low in ldcs compared to the developed countries the most appropriate techniques for ldcs from an economic point of view are likely to be the laborintensive ones if we suppose that there is a single most efficient technique for each industry and if it technologically requires labor and capital in fixed proportions the most appropriate industries for ldcs are likely to be the labor intensive ones this is because of the close correspondence between industries and their technological requirements on an international scale this appropriateness is given some support by the heckscher ohlin theorem of international specialization in production as is well known this theorem indicates subject to various assusmptions that countries should specialize in the production of goods that make use of their relatively abundant factors of production the aim of this paper is to identify appropriate industries for bangladesh in view of the relative availability of labor and capital and taking into account the amount of labor and capital needed both directly and indirectly to produce output for each industry unfortunately as specified below a number of previous studies of appropriate techniques and industries have ignored the indirect requirements for labor and capital needed to produce the various intermediate products used in these industries interindustry analysis based on the assumption that the adopted techniques require inputs to be combined in fixed

an introduction to the theory of rational expectations under asymmetric information every good economics textbook contains the cliche that market prices provide signals which facilitate the allocation of resources to their best use in a world not subject to random shocks consumers and producers when faced with competitive prices need look no further than their own preferences or production technology to be able to make a decision they need give no thought to the tastes endowments or technology of other agents however in a world subject to random shocks this is no longer the case agents are faced with the problem of forecasting future states of nature and more importantly of forecasting the impact of these states on the actions of other agents rational expectations theories provide a model of how agents make those forecasts in a world subject to random shocks it will be the case that agents acquire or at least attempt to acquire information about the future realization of the shocks it will in general be the case that different agents have access to different information the fact that information is dispersed throughout the economy has the potential to cause a misallocation of resources relative to what would be the case if all agents knew everything an efficient allocation of resources will in general require the transfer of information from consumers who have some information about their future demands to producers who can take current actions to mitigate avoidable scarcities or surpluses though many classical and neo classical writers emphasize the informational role of prices the standard marshallian or walrasian model of competitive equilibrium does not involve prices transferring information across traders the purpose of this paper is to show that rational expectations models are radically different from walrasian models in an economy where traders have diverse information this is demonstrated by showing that unlike what occurs in a walrasian equilibrium of an economy with heterogeneous information if there is a complete set of insurance markets and utility is additively separable over time then there exists a rational expectations equilibrium which gives consumers the same allocation as if each consumer has access to all of the economy s information this implies that under the above assumptions a central planner with all the economy s information could not pareto dominate the competitive allocation achieved when traders have diverse information and rational expectations this paper makes no attempt to survey the literature on rational expectations the reader is referred to shiller 1978 barro 1981 for a survey of macroeconomics and rational expectations and radner 1980 for a survey of the microeconomics and mathematical theory of rational expectations this paper will however try to outline the evolution of the rational expectations concept from a notion of optimal forecasting to a virtually complete departure from the walrasian model of equilibrium the rest of this section is devoted to a discussion of pre rational expectations ideas

genetic algorithms and inflationary economies abstract this paper studies overlapping generations economies in which agents use genetic algorithms to learn correct decision rules the results of computer simulations show that a genetic algorithm converges to the unique monetary steady state in case of a constant money supply policy and to the low inflation stationary equilibrium in case of a constant real deficit financed through seignorage features of the genetic algorithm adaptation are compared to the performance of other learning algorithms and to the behavior observed in experiments with human subjects in the same olg environments

rational choice the contrast between economics and psychology rational choice the published record of a conference on economics and psychology frames the issues as a contest between economic theory and the falsifying evidence from psychology according to a third perspective that of experimental economics most standard theory provides a correct first approximation in predicting motivated behavior in laboratory experimental markets but the theory is incomplete particularly in articulating convergence processes in time and in ignoring decision cost this view has roots in the work of herbert simon and sidney siegel but it is not plainly represented in contemporary research in economic pyschology