Dependence calibration and portfolio fit with factor-based subordinators

The paper explores the properties of a class of multivariate Lévy processes used for asset returns. We focus on describing both linear and non-linear dependence in an economic sensible and empirically appropriate way. The processes are subordinated Brownian motions. The subordinator has a common and an idiosyncratic component, to reflect the properties of trade, which it represents. A calibration to a portfolio of 10 US stock indices returns over the period 2009–2013 shows that the hyperbolic specification has a very good fit to marginal distributions, to the overall correlation matrix and to the return distribution of both long-only and long-short random portfolios, which also incorporate non-linear dependence. Their tail behaviour is also well captured by the variance gamma specification. The main message is not only the goodness of fit, but also the flexibility in capturing dependence and the ease of calibration on large sets of returns.     

THEORY AND PRACTICE OF GVAR MODELLING

The Global Vector Autoregressive (GVAR) approach has proven to be a very useful approach to analyse interactions in the global macroeconomy and other data networks where both the cross‐section and the time dimensions are large. This paper surveys the latest developments in the GVAR modelling, examining both the theoretical foundations of the approach and its numerous empirical applications. We provide a synthesis of existing literature and highlight areas for future research.     

基于主体建模方法及其在宏观经济学中的应用

本文介绍了一种新型宏观经济学研究范式———基于主体建模方法。与主流的动态随机一般均衡模型相比,基于主体建模方法能更好地描述实际生活中经济主体的有限理性和适应性预期的行为,同时它还可以模拟复杂性系统中的异质性主体之间的交互作用,从而研究经济系统的演化过程及其宏观特征的“涌现”过程。此外,本文还介绍了基于主题建模方法在货币政策和经济波动理论中的应用：在政策分析中,基于主题建模方法能大量模拟市场参与者决策的“动物精神”和“羊群效应”,即使没有外部冲击,也可能形成金融危机等非均衡经济现象。随着计算机水平的发展,基于主题建模方法必将成为经济学分析的一个有力的新工具。     

Technology,market policies and institutional reform for sustainable land use in southern Mali

To identify appropriate interventions that support sustainable land use; a farm household modelling approach is applied to analyze micro-economic supply reactions to various policy measures. The modelling framework links agro-technical and economic data, and takes both production and consumption decisions into account, allowing land use and production technology adjustments in accordance with farm household objectives. Different types of farm households are distinguished on the basis of their resource endowments, savings coefficients and time discount rate. Actual and alternative (sustainable) cropping and livestock activities for different weather regimes are defined for southern Mali. The effects on sustainable land use and expected farm household welfare of adopting alternative technologies and modifying prices, transaction costs, access to credit and land taxes are demonstrated. Even with full information on sustainable technologies, strong policy interventions are required to halt soil degradation. Structural policies proved to be more effective than price policies to reduce soil degradation while maintaining positive income effects. When prices are determined endogenously, structural policy loses some effectiveness as an incentive for sustainable land use due to the effect of additional supply on local cereal and meat Prices.     

Impacts of intermediate trade on sector structure

Structural changes, i.e. long-run changes in the agriculture-manufacturing-services-structure, are a key property of growth and development processes with massive impacts on economy and society and are part of actual debates regarding policy in developing and developed economies. While traditional literature has attempted to explain structural changes by using autarkic models, recent literature has emphasised the importance of deriving theories of structural change using open economy settings. We elaborate on the impacts of intermediate trade on sector structure. In particular, we study how import of intermediate products, which is increasingly feasible due to improvements in transport technology and political integration, affects sector structure in a multi-sector growth model with capital accumulation. This topic has not been studied in the previous literature on structural change in open economies, despite the fact that intermediate imports and capital accumulation are central aspects of modern developing and developed economies. We show that the impacts of intermediate trade on sector structure depend on three factors: productivity gains from trade, specialisation in international trade and development stage. Depending on the constellation of these factors, intermediate trade may accelerate, decelerate or have no effect on structural change. Thus, the effects of intermediate trade may vary strongly across countries.     

Evaluating the potential of agent-based modelling to capture consumer grocery retail store choice behaviours

Evolving consumer behaviours with regards to store and channel choice, shopping frequency, shopping mission and spending heighten the need for robust spatial modelling tools for use within retail analytics. In this paper, we report on collaboration with a major UK grocery retailer to assess the feasibility of modelling consumer store choice behaviours at the level of the individual consumer. We benefit from very rare access to our collaborating retailers’ customer data which we use to develop a proof-of-concept agent-based model (ABM). Utilising our collaborating retailers’ loyalty card database, we extract key consumer behaviours in relation to shopping frequency, mission, store choice and spending. We build these observed behaviours into our ABM, based on a simplified urban environment, calibrated and validated against observed consumer data. Our ABM is able to capture key spatiotemporal drivers of consumer store choice behaviour at the individual level. Our findings could afford new opportunities for spatial modelling within the retail sector, enabling the complexity of consumer behaviours to be captured and simulated within a novel modelling framework. We reflect on further model development required for use in a commercial context for location-based decision-making.     

Position-Dependent order effects on the prediction of consumer preferences in repeated choice experiments

Using stated choice data collected by experimental design with repeated choice tasks, this study developed an approach to quantify the position-dependent order effects on the prediction of preferences and marginal willingness to pay for product attributes. Results showed that repeated choice tasks allow learning to occur. Models with order effect adjustments showed significant improvements in goodness of fit. Attribute-specific polynomial trends showed the best fit among all models, which could possibly be explained by respondents’ familiarity and sensitivity to different product attributes. Repeated-choice experiments have a good potential to capture consumer preferences more accurately than the single-choice design. But order effects need to be taken into account for preferences and market prediction.     

A comparison of regret-based and utility-based discrete choice modelling – an empirical illustration with hospital bed choice

There is some concern that the unobserved preference heterogeneity in random utility maximization theory-based discrete choice experiment modelling is an important source of error variability. The randomness in utility is often interpreted as interpersonal preference heterogeneity but it can also be intrapersonal random variation in preferences. We compare utility maximization and regret minimization-based choice models’ sensitivity to individual heterogeneity, examine differences between two consecrated models and validate with empirical illustrations. We use frequency of category (public, semi-private, and private) of bed chosen from Swiss cross-sectional datasets (2007–2012) to compare two approaches – utility maximization and regret minimization by applying multinomial logit (MNL) models in regard to the variances in utility (regret) function, goodness-of-fit and predicted marginal effects (pseudo-elasticity) of additional payment. We find parameters with the same sign and estimates with almost same order of magnitude in both the approaches. The statistical significance of attribute effects is consistent in all variants of utility -based MNL models while effects of different attributes are significant only in heteroskedastic extreme value (HEV) variant of regret-based MNL models. This empirical illustration suggests that HEV variant of regret-based models perform better in capturing attribute effects in choice behaviour.     

Expanding Socio-economics in Four Dimensions

Abstract

During the last decades the rapid progress in the fields of complex modelling and simulationor in the cognitive and the life sciences was not accompanied by a similar advancement of the socio-economic research tradition itself. Socio-economics as a hybrid field for the complex dynamics of modern societies across their micro-, meso- and macro-levels has still a long way to go in order to reach its full potential. The present article provides a general outline for expanding and advancing socio-economics along four different dimensions which should be able to produce a significant take-off for socio-economic theories, models, methods and mechanisms.