Growth-equity decomposition of a change in poverty: An axiomatic approach

This paper studies a class of subgroup decomposable poverty measures whose changes may be decomposed into a growth component and a redistribution component. A set of reasonable axioms leads inexorably to a combination of the Watts measure and the poverty gap measure.     

Individual Performance in Turbulent Environments: The Role of Organizational Learning Capability and Employee Flexibility

Organizational learning capability (OLC) and employee flexibility help firms navigate the challenges faced by organizations operating in turbulent environments. OLC includes dimensions such as experimentation, risk taking, openness, dialogue, and participative decision making. Employee flexibility is considered a crucial tool for strategic human resource management in tackling environmental turbulence. Accordingly, we pose the following research question: how, and to what extent, is individual performance enhanced by OLC and employee flexibility in turbulent environments? The major impact that environmental turbulence has on change and flexibility requirements suggests that employee flexibility plays an important role in the impact OLC has on individual performance. However, we found no prior studies that explicitly analyzed this mediating function of employee flexibility. In this study, we tested three hypotheses that link OLC and individual performance, OLC and employee flexibility, and employee flexibility and individual performance. We applied a structural equation methodology, using partial least squares path modeling, to a sample of 174 academics at a Latin American university (a highly turbulent context). Our results show employee flexibility fully mediates the relation between OLC and individual performance given the presence of environmental turbulence. © 2015 Wiley Periodicals, Inc.     

Path dependent volatility

We propose a general class of non-constant volatility models with dependence on the past. The framework includes path-dependent volatility models such as that by Hobson and Rogers and also path dependent contracts such as options of Asian style. A key feature of the model is that market completeness is preserved. Some empirical analysis, based on the comparison with standard local volatility and Heston models, shows the effectiveness of the path dependent volatility. In particular, it turns out that, when large market movements occur, the tracking errors of Heston minimum-variance hedging are up to twice the hedging errors of a path dependent volatility model.      

Bounded interest rate feedback rules in continuous-time

This paper analyzes the dynamic consequences of interest rate feedback rules in a flexible-price model where money enters the utility function. Two alternative rules are considered based on past or predicted inflation rates. The main feature is to consider inflation rates that are selected over a bounded time horizon. We prove that if the Central Bank's forecast horizon is not too long, an active and forward-looking monetary policy is not destabilizing: the equilibrium trajectory is unique and monotonic. This is an advantage with respect to active and backward-looking policies that are shown to lead to a unique but fluctuating dynamic.     

中国工业企业数据库(1999~2013)的使用研究：基于插值处理方法的比较分析

中国工业企业数据库已经成为研究中国微观企业活动的首选数据库，但是数据库中关键指标的缺失严重影响了数据库的更新和使用。本文在借鉴主要文献处理方法的基础上，先后采用单值移动时序平滑法、MICE1、MICE2、MMICE1和MMICE2五种插补方法对数据库进行完善，从而将中国工业企业数据库延伸至2013年，并通过计算企业全要素生产率来评估各种插补方法的相对有效性。研究表明：在这五种插值方法中，单值移动时序平滑法和MMICE1是两种最为有效的插值方法，不仅可以实现插值前后的数据库特征一致，而且能够实现所计算的全要素生产率的数据结构特征一致。值得强调的是，在完善数据库和计算全要素生产率方面，前者因为处理过程简单因而是一种相对经济的方法，而后者因为能够保留更多样本信息因而是一种相对有效的方法。本文研究价值体现在对使用中国工业企业数据库提供了基础性研究工作。     

A stochastic differential equation approach to the analysis of the 2017 and 2019 UK general election polls

Human dynamics and sociophysics build on statistical models that can shed light on and add to our understanding of social phenomena. We propose a generative model based on a stochastic differential equation that enables us to model the opinion polls leading up to the 2017 and 2019 UK general elections and to make predictions relating to the actual results of the elections. After a brief analysis of the time series of the poll results, we provide empirical evidence that the gamma distribution, which is often used in financial modelling, fits the marginal distribution of this time series. We demonstrate that the proposed poll-based forecasting model may improve upon predictions based solely on polls. The method uses the Euler–Maruyama method to simulate the time series, measuring the prediction error with the mean absolute error and the root mean square error, and as such could be used as part of a toolkit for forecasting elections.     

Multiple solutions in systems of functional differential equations

This paper proposes conditions for the existence and uniqueness of solutions to systems of linear differential or algebraic equations with delays or advances, in which some variables may be non-predetermined. These conditions represent the counterpart to the Blanchard and Kahn conditions for the functional equations under consideration. To illustrate the mathematical results, applications to an overlapping generations model and a time-to-build model are developed.     

De Moivre's Poisson Approximation to the Binomial

In his first work on probability, written in 1711, Abraham De Moivre looked at the problem of finding the number of trials required in a binomial experiment to achieve a probability of 1/2 of finding at least some given number of successes. He looked at two cases: when the probability of success  p  = 1/2 and when  p  is small but  n , the number of trials, is large. In the latter case, unlike other problems that he solved in probability, De Moivre never revealed his method of solution. We explore the solution that De Moivre originally suggests and find that his method does not work. We explore other numerical solutions and put forward the suggestion that De Moivre relied on a very cumbersome and tedious method of solution based on his earlier work on series in the 1690s. Since his method was neither quick nor mathematically elegant, he never revealed the method that he used to obtain his numerical solutions.     

The dynamics of online word-of-mouth and product sales—An empirical investigation of the movie industry

There are growing interests in understanding how word-of-mouth (WOM) on the Internet is generated and how it influences consumers’ purchase decisions at retail outlets. A unique aspect of the WOM effect is the presence of a positive feedback mechanism between WOM and retail sales. We characterize the process through a dynamic simultaneous equation system, in which we separate the effect of online WOM as both a precursor to and an outcome of retail sales. We apply our approach to the movie industry, showing that both a movie's box office revenue and WOM valence significantly influence WOM volume. WOM volume in turn leads to higher box office performance. This positive feedback mechanism highlights the importance of WOM in generating and sustaining retail revenue.