Market design for standardization problems with agent-based social simulation

This paper provides a computational market model with technological competitions among standards and presents simulations of various scenarios concerning standardization problems. The market model has three features: (1) economic entities such as consumers and firms are regarded as autonomous agents; (2) micro interactions among consumer agents or firm agents have essential mechanisms interpretable in real markets; and (3) consumers’ preferences and firms’ technologies co-affect their evolutionary behavior. In recent years, consumers have experienced various inconveniences from de facto competition based on a market mechanism. Standardization communities or committees such as the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) need to design a compatible standard or a de jure standard in a market. However, it is difficult for market designers to decide a method or timing for the standardization. Here, by introducing a novel technique used in agent-based social simulation (ABSS), which we call “scenario analysis,” we aim to support such decision making. Scenario analysis provides the possible market changes that can occur following implementation of a design policy under a specific market situation and the market mechanisms that generate these market changes.     

Validation in agent-based models: An investigation on the CATS model

In this paper we deal with some validation experiments on the complex adaptive trivial system (CATS) model proposed in Gallegati et al. [Gallegati, M., Giulioni, G., Palestrini, A., Delli Gatti, D., 2003a. Financial fragility, patterns of firms’ entry and exit and aggregate dynamics. Journal of Economic Behavior and Organization 51, 79–97; Gallegati, M., Delli Gatti, D., Di Guilmi, C., Gaffeo, E., Giulioni, G., Palestrini, A., 2005. A new approach to business fluctuations: heterogeneous interacting agents, scaling laws and financial fragility. Journal of Economic Behavior and Organization 56, 489–512]. In particular starting from a sample of Italian firms included in the AIDA database, we perform several ex post validation experiments over the simulation period 1996–2001. In the experiments, the model parameters have been estimated using actual data and the initial set up consists of a sample of agents in 1996. The CATS model is then simulated over the period 1996–2001. Using alternative validation techniques, the simulations’ results are ex post validated respect to the actual data.     

Referral hiring, endogenous social networks, and inequality: an agent-based analysis

The importance of referral hiring, which is workers finding employment via social contacts, is nowadays an empirically well documented fact. It also has been shown that social networks for finding jobs can create stratification. These analyses are, by and large, based on exogenous network structures. We go beyond the existing work by building an agent-based model of the labor market in which the social network of potential referees is endogenous. Workers invest some of their endowments into building up and fostering their social networks as an insurance device against future job losses. We look into the manner in which social networks and inequality respond to increased uncertainty in the labor market. We find that larger variability in firms’ labor demand reduces workers’ efforts put into social networks, leading to lower inequality.     

Twentieth-century demographic processes and social problems

The causes and consequences of current world population growth rates are examined. Future prospects for world population growth are discussed, with a focus on the resulting social and economic problems in developing countries. Several approaches to the analysis of the current global demographic situation are described and evaluated.     

Equilibrium dynamics in discrete-time endogenous growth models with social constant returns

The existing literature establishes possibilities of local determinacy and dynamic indeterminacy in continuous-time two-sector models of endogenous growth with social constant returns. The necessary and sufficient condition for local determinacy is that the factor intensity rankings of the two sectors are consistent in the private/physical and social/value sense. The necessary and sufficient condition for dynamic indeterminacy is that the final (consumable) good sector is human (pure) capital intensive in the private sense but physical (consumable) capital intensive in the social sense. This paper re-examines the dynamic properties in a discrete-time endogenous growth framework and finds that conventional propositions obtained in continuous time need not be valid. It is shown that the established necessary and sufficient conditions on factor intensity rankings for local determinacy and dynamic indeterminacy are neither sufficient nor necessary, as the magnitudes of time preference and capital depreciation rates both play essential roles. We have benefitted from discussion with Robert Becker, Eric Bond, Michael Kaganovich, Karl Shell and participants of the Midwest Macroeconomic Conference in Chicago and the Midwest Economic Theory and International Trade Meetings at Indiana University. The fourth author acknowledges financial support from the Institute of Economics and Business Administration of Kobe University and the Institute of Economic Research of Kyoto University to enable this international collaboration.     

Progressive taxation and macroeconomic stability in two-sector models with social constant returns

It has been shown that, in the two-sector Benhabib–Farmer–Guo model with technologies of social increasing returns that exhibits indeterminacy, progressive income taxes de-stabilize the economy. This paper revisits the robustness of the tax implication in the two-sector Benhabib–Nishimura model with technologies of social constant returns that exhibits indeterminacy. We show that a progressive income tax stabilizes the economy against sunspot fluctuations, and thus the tax implication based on the two-sector Benhabib–Farmer–Guo model is not robust.     

Brownian agent-based technology forecasting

Today's innovation process is best characterized by nonlinearity and interaction. Agent-based models build on these concepts, but have not been useful in practice because they are either too complex or too simple to make a good match with reality. As a remedy, we employ a Brownian agent model with intermediate complexity to produce value-added technology forecasting. As an illustration with Korea's software industry data, computer simulation is carried out. Attracted by higher technology value, agents concentrate on specific technology regions, and form co-existing major technology regions of high density. A rough comparison with actual software production data exhibits a fair reflection of reality, and supports the underlying idea that economic motivation of agents should be considered.     

Assessing the potential impact of Microfinance with agent-based modeling

Recent empirical results have cast doubt on the value of Microfinance as a tool for reducing poverty. But, the difficulty lies in evaluating the impact of Microfinance in a world where the Microfinance institutions, their borrowers, and government policies are constantly changing. There is a need for a comprehensive and transparent framework to develop the theoretical grounds for believing in (or against) the efficacy of Microfinance, which can at the same time be used as a testing ground for policymakers. This paper presents a first attempt to develop an agent-based modeling (ABM) framework for pre-policy-implementation testing of the effects of Microfinance. Under the ABM paradigm, a set of behaviors for individual agents in the economy is used to construct a simulation whereby random interaction allows agents to change their state over time. Simulation of the model in different scenarios supported all our intuitions about Microfinance; in particular, there was positive impact of Microfinance on the wealth level of the poor. It was found that increase of available funds, easy access for producers and lower interest rates increase the effectiveness of Microfinance.     

A multi-stage race model with strategic interaction: An agent-based simulation approach

We consider a multi-stage race characterized by technological uncertainty and winner-take-all stakes. A number of studies have found that players in such a race tend to behave strategically by adjusting their effort levels according to their relative ranks. The aim of the present study was to examine the dynamics and the results of such interaction. For this purpose, we employed an agent-based computational approach that enabled us to better understand the dynamics of a race, particularly those in which players exhibit heterogeneous behaviors. The results found that strategic interaction decreases the total cost but also results in delaying the completion of a race. Also, it was discovered, larger budgets rather than strategy differences have more significant effects on the probability of players winning a race. Finally, our study suggested that early preemption is an effective strategy that can improve the probability of winning races substantially.     

Consumption taxation, social status and indeterminacy in models of endogenous growth with elastic labor supply

In this paper, we examine the effects of consumption taxation on long-run growth in an infinitely lived representative-agent model of endogenous growth with endogenous labor supply in which the desire for social status induces private agents to care about others’ wealth or consumption levels. This analysis shows that the increase in consumption taxation raises (reduces) the long-run growth rate when the equilibrium path is locally indeterminate (determinate), provided the desire for social status is not too strong in the relative wealth model. By contrast, in the consumption externalities model, the same result holds, if the Frisch labor supply and labor demand curves have the ‘normal’ slopes at their intersection point, while the result is reversed if these two curves have the ‘wrong’ slopes.     

A stress test of fairness measures in models of social utility

Summary. Current social utility models posit fairness as a motive for certain types of strategic behavior. The models differ, however, with respect to how fairness is measured. Distribution models measure fairness in terms of relative payoff comparisons. Reciprocal-kindness models measure fairness in terms of gifts given and gifts received. Reference points play an important role in both measures, but the reference points in reciprocal-kindness models are conditioned on the actions available to players, whereas those in distributive models are not. Data from an ultimatum game experiment that stress tests the kindness measure is consistent with the distributive measure. Data from an experiment that stress tests the distributive measure is inconsistent with the distributive measure, but moves in the direction opposite that implied by the kindness measure. A measure that combines relative payoff comparisons with a reference point conditioned on feasible actions provides a first approximation to our data.Received: 12 August 2002, Revised: 27 November 2003, JEL Classification Numbers: C78, C91, D63. Correspondence to: Axel OckenfelsBolton gratefully acknowledges the support of the National Science Foundation. Ockenfels thanks Alvin Roth and the Harvard Business School for their generous hospitality, and the Deutsche Forschungsgemeinschaft for their support through the Emmy Noether-program. Both authors gratefully acknowledge the hospitality of the Making Choices project at the Center for Interdisciplinary Research, University of Bielefeld during the summer of 2000. We also thank an anonymous referee and seminar participants in Bielefeld, Boston, Columbus, Harvard, and Jena for helpful comments.     

Clues for discriminating between moving average and autoregressive models in spatial processes

In this paper we try to provide additional insight into the problem of how to discriminate between the two most common spatial processes: the autoregressive and the moving average. This problem, whose analogous time series is apparently simple, acquires a certain complexity when it is considered in an irregular system of spatial units, mainly because there are few tools to carry out this discussion. Nevertheless, even with this lack, we believe that it is possible to make some progress using the methods available at present. In this paper we discuss the advantages and inconveniences of the different techniques that can help us to discriminate between both processes. We finish off the examination with a Monte Carlo exercise, and an application to the European regional income, which has enabled us to better understand the performance of several proposals such as the Lagrange Multipliers, the so-called Variance criterion and the tests of Vuong and Clarke.      

Regional differences in the production processes of financial and social outputs of microfinance institutions

This study uses panel data of microfinance institutions across the world to compare production processes across regions, assess the relevance of unobserved heterogeneity and estimate economies of scale. Comparing a financial production process to a multidimensional production process that accounts for the presence of outreach in the objective function suggests that financial and social output reflect complements in South Asia but not in other regions. Furthermore, we find substantial economies of scale for a pure financial production process. However, accounting for outreach lowers estimated economies of scale, suggesting that producing outreach creates high transaction costs and requires exploitation of local knowledge.     

Applying agent-based modeling to the evolution of eco-industrial systems

Agent-based modeling is simply a modeling technique for describing complex adaptive systems in a form that can be solved by computers. In this paper, agent-based modeling is applied to eco-industrial systems to gain new insights into their behavior. The factory in the eco-industrial systems is taken as an agent, and the objects, attributes and behaviors are determined. Some important interaction mechanisms between agents are also designed. Besides, the sustainability evolution is also studied through emergy theory. More importantly, a new concept, the Internal-flow emergy, is used to indicate the evolution direction of an eco-industrial system. Finally, a hypothetical eco-industrial park utilizing natural gas and halite as the main raw material inputs is adopted as a case study to illustrate the effectiveness of the agent-based modeling.     

Adaptation processes in the context of climate change: a social and environmental psychology perspective

An informed multidisciplinary understanding of the ways in which people experience, appraise, adapt, and respond to global climate change is a prerequisite to effectively managing the transition to a sustainable economy. In this paper, we argue that climate science has to date failed to fully appreciate the contribution that social and environmental psychology can make to such an understanding. We draw on findings from two large national Australian surveys to demonstrate how this perspective can contribute to knowledge, understanding, and policy formulation. Central to this perspective are processes of psychological adaptation, that is, processes through which individuals orient towards, make sense of, and ultimately come to terms with, the threat and reality of climate change. Such adaptive processes are shown to mediate relationships between environmental experiences and behavior, and hence provide the foundation for environmentally-friendly lifestyles. Rather than assuming that external sanctions and incentives are sufficient to engender sustainable lifestyle changes, a social and environmental psychology approach recognises and explores the complexities of the transactions that occur between individuals’ internal and external environments, emphasizes the importance of intrinsic motivation and self-determination, and suggests the need for initiatives that promote behaviors that are both environmentally and psychologically significant.     

Imitation processes with small mutations

This note characterizes the impact of adding rare stochastic mutations to an “imitation dynamic,” meaning a process with the properties that absent strategies remain absent, and non-homogeneous states are transient. The resulting system will spend almost all of its time at the absorbing states of the no-mutation process. The work of Freidlin and Wentzell [Random Perturbations of Dynamical Systems, Springer, New York, 1984] and its extensions provide a general algorithm for calculating the limit distribution, but this algorithm can be complicated to apply. This note provides a simpler and more intuitive algorithm. Loosely speaking, in a process with K strategies, it is sufficient to find the invariant distribution of a K×K Markov matrix on the K homogeneous states, where the probability of a transit from “all play i” to “all play j” is the probability of a transition from the state “all agents but 1 play i, 1 plays j” to the state “all play j”.     

On positional consumption and technological innovation: an agent-based model

Positional behaviour is arguably a source of social externalities. Remedies for this market failure are defended by some authors and rejected by others. One of the issues discussed is the role that the competition for positional goods may have in generating technological innovation. This article aims to contribute to the understanding of the dynamics of this process through the use of an agent-based model. Simulations show a plausible dynamics of the process of technological innovation as generated by consumption of positional nature. An interpretation of the results in the scope of the policy discussion in question is provided. The influence of key factors such as income inequality, the materialization of the Hirsch conjecture, and characteristics of the network of relative preferences, is analised. We also frame the potential interest of positional consumption and this model in particular in the context of the ongoing discussion among evolutionary economists on the behaviour of demand.