
on Computational Economics 
Issue of 2012‒11‒17
eight papers chosen by 
By:  Westerhoff, Frank; Franke, Reiner 
Abstract:  With the help of two examples, we illustrate the usefulness of agentbased models as a tool for economic policy design. In our first example, we apply a financial market model in which the order flow of speculators, relying on technical and fundamental analysis, generates intricate price dynamics. In our second example, we apply a Keynesiantype goods market model in which the investment behavior of firms, relying on extrapolative and regressive predictors, generates complex business cycles. We add a central authority to these two setups and explore the impact of simple intervention strategies on the model dynamics. Based on these experiments, we conclude that agentbased models may help us to understand how markets function and to evaluate the effectiveness of various stabilization policies.  
Keywords:  Agentbased models,Economic policy design,Financial markets,Goods markets,Simulation analysis 
JEL:  C63 D84 E32 G12 
Date:  2012 
URL:  http://d.repec.org/n?u=RePEc:zbw:bamber:88&r=cmp 
By:  Michael Neugart; Matteo G. Richiardi 
Abstract:  We review the literature on agentbased labor market models by tracing its roots to the microsimulation literature, and surveying a selection of contributions made since the work by Bergmann (1974) and Eliasson (1976). Agentbased models have been applied to explain stylized facts of labor markets as well as for labor market policy evaluations. They also constitute a major part in agentbased macroeconomic models. Besides reviewing the various results achieved, we discuss modeling choices with respect to agents’ behavior and the structure of interaction. Our overall assessment is that agentbased labor market models have given us valuable insights into the functioning of labor markets and the consequences of labor market policies, and that they will increasingly become an essential tool of analysis, in particular when the construction of large macromodels is involved. 
Date:  2012 
URL:  http://d.repec.org/n?u=RePEc:cca:wplabo:125&r=cmp 
By:  Iori, G.; Porter, J. 
Date:  2012 
URL:  http://d.repec.org/n?u=RePEc:cty:dpaper:12/08&r=cmp 
By:  Paolo Pellizzari (Department of Economics, University Of Venice Cà Foscari); Dino Rizzi (Department of Economics, University Of Venice Cà Foscari) 
Abstract:  In this paper we present a model of tax compliance with heterogeneous agents who maximize their individual utility based on income and the conjectured level of per capita public expenditure. We formally include psychological drivers in this model. These drivers affect individual behavior, such as risk aversion, together with appreciation of public expenditure, expectations about peers’ compliance and a natural inclination to comply, all of which we summarize in a quality termed “citizenship”. The enforcement system, based on random inspections, is standard and only partially known to agents. The agentbased model is simulated under a variety of settings, representing different “societies”. We use the artificial data produced by the model to estimate the effects of taxpayers’ traits on personal tax behavior and to build a compliance societal slippery slope. At the individual level, we find a positive dependence of compliance on all variables, with the significant exception of the tax rate, which has a negative impact. As far as societies are concerned, we show how aggregate tax compliance depends on composite indices of citizenship and power, and we find that the former is more important than the latter. 
Keywords:  Tax evasion, public expenditure, agentbased models 
JEL:  H26 H40 C63 
Date:  2012 
URL:  http://d.repec.org/n?u=RePEc:ven:wpaper:2012_24&r=cmp 
By:  Ambra Poggi; Matteo G. Richiardi 
Abstract:  Dynamic microsimulation modeling involves two stages: estimation and forecasting. Unobserved heterogeneity is often considered in estimation, but not in forecasting, beyond trivial cases. Nontrivial cases involve individuals that enter the simulation with a history of previous outcomes. We show that the simple solutions of attributing to these individuals a null effect or a random draw from the estimated unconditional distributions lead to biased forecasts, which are often worse than those obtained neglecting unobserved heterogeneity altogether. We then present a first implementation of the Rank method, a new algorithm for attributing the individual effects to the simulation sample which greatly simplifies those already known in the literature. Outofsample validation of our model shows that correctly imputing unobserved heterogeneity significantly improves the quality of the forecasts. 
Keywords:  Dynamic microsimulation, Unobserved heterogeneity, Validation, Rank method, Assignment algorithms, Female labor force participation, Italy 
JEL:  C53 C18 C23 C25 J11 J12 J21 
Date:  2012 
URL:  http://d.repec.org/n?u=RePEc:cca:wplabo:124&r=cmp 
By:  Karolina Bujok; Ben Hambly; Christoph Reisinger 
Abstract:  We consider $N$ Bernoulli random variables, which are independent conditional on a common random factor determining their probability distribution. We show that certain expected functionals of the proportion $L_N$ of variables in a given state converge at rate 1/N as $N\rightarrow \infty$. Based on these results, we propose a multilevel simulation algorithm using a family of sequences with increasing length, to obtain estimators for these expected functionals with a meansquare error of $\epsilon^2$ and computational complexity of order $\epsilon^{2}$, independent of $N$. In particular, this optimal complexity order also holds for the infinitedimensional limit. Numerical examples are presented for tranche spreads of basket credit derivatives. 
Date:  2012–11 
URL:  http://d.repec.org/n?u=RePEc:arx:papers:1211.0707&r=cmp 
By:  Photis, Yorgos N. 
Abstract:  The main purpose of this paper is the formulation of a methodological approach for the definition of homogenous spatial clusters, taking into account both geographical and descriptive characteristics. The proposed methodology, is substantiated by SPiRAL (SPatial Integration and Redistricting ALgorithm), a constrainedbased spatial clustering algorithm, whose successive steps focus on the analysis of the characteristics of the areas being integrated, the designation of the spatial clusters and the validity of a joining criterion. We applied the methodological approach and used SPiRAL to solve a realistic electoral redistricting problem. Namely, the redefinition of the electoral districts of the Prefecture of Lakonia in Greece. The results demonstrate an improved layout of the study area’s electoral map as far as the problem’s criteria and constraints are concerned (adjacency, population and size), justifying in this respect the perspectives and potential of our approach in the analysis and confrontation of similar problems. 
Keywords:  Spatial clustering; GIS; constraintbased algorithm; electoral districts; Greece 
JEL:  R53 O2 D72 
Date:  2012–10 
URL:  http://d.repec.org/n?u=RePEc:pra:mprapa:42398&r=cmp 
By:  Salvatore Federico; Paul Gassiat; Fausto Gozzi 
Abstract:  We study a problem of optimal investment/consumption over an infinite horizon in a market consisting of two possibly correlated assets: one liquid and one illiquid. The liquid asset is observed and can be traded continuously, while the illiquid one can be traded only at discrete random times corresponding to the jumps of a Poisson process with intensity $\lambda$, is observed at the trading dates, and is partially observed between two different trading dates. The problem is a nonstandard mixed discrete/continuous optimal control problem which we face by the dynamic programming approach. When the utility has a general form we prove that the value function is the unique viscosity solution of the HJB equation and, assuming sufficient regularity of the value function, we give a verification theorem that describes the optimal investment strategies for the illiquid asset. In the case of power utility, we prove the regularity of the value function needed to apply the verification theorem, providing the complete theoretical solution of the problem. This allows us to perform numerical simulation, so to analyze the impact of time illiquidity in this mixed market and how this impact is affected by the degree of observation. 
Date:  2012–11 
URL:  http://d.repec.org/n?u=RePEc:arx:papers:1211.1285&r=cmp 