Aggregate accounting research and development expenditures and the prediction of real gross domestic product

The role of accounting information for public policy making has received increased attention in recent years. Konchitchki and Patatoukas, 2014a, Konchitchki and Patatoukas, 2014b demonstrate that growth in aggregate accounting earnings can predict future growth in nominal and real Gross Domestic Product (GDP). We extend the micro to macro literature by decomposing earnings into the R&D and pre-R&D components. Using the Almon (1965) finite distributed lag model, we find that both components can predict future real GDP growth with different lead-lag structures. Importantly, this decomposition significantly increases the explanatory power of the predictive model using accounting information. Aggregate accounting R&D can predict real GDP through the personal consumption, business investment, and net export channels of GDP. Our study extends prior research on the forecasting usefulness of accounting information at the aggregate level and has practical implications for macro forecasting and for public policy making regarding innovative activities of publicly listed firms.     

Estimating Recreational User Counts

This article outlines a methodology for estimating the number of individual visitors to a set of recreational sites, as well as counts of specific visitor groups. The model is designed for sets of sites characterized by: ( a ) unrestricted recreation from a wide and partially unknown geographic market; ( b ) individuals who may visit more than one site; ( c ) accurate visitation (gate) counts from each site. The model provides consistent estimates of the total number of individual visitors, based on information embedded in site-level count and survey data. Monte Carlo analysis and an empirical application illustrate the properties of visitor count estimates.     

村落视野中的人口“数字游戏”及其省思

在特定的村落场景中,探讨了人口“数字游戏”的现状、运作规则及其生成机理。村官在数据建构时玩弄的“数字游戏”可分两类一种是出于政治目的,人为地虚报或瞒报数字;另一种是因袭传统的统计标准,随意报送与人口现实不符的数据。前者是基层政治操纵的结果,后者则折射了当下科学统计标准的阙如。在政治体制缺陷与科学统计缺失的双重夹击下,村级的官方统计不求准确,有的甚至是扭曲的。乡村统计实践追根溯源仍在很大程度上为政治所裹挟。这一切彰显了有法不依的尴尬和学术滞后现实的悲哀。强化问责惩处机制自不必说,改变用数字来衡量政绩的体制也势在必行。而以天下为己任的知识者也应反躬自省在解决与现实剥离的含混统计以及在面向现实生活上的使命。     

Positive Feedback and Path Dependence Using the Law of Large Numbers

Economists have become interested in the behavior of random processes with positive feedback but have sometimes found it difficult to introduce students to this research. Simulation of the law of large numbers with increasing amounts of feedback provides a convenient framework for such discussion and facilitates a nontechnical introduction to recent work on path dependence.     

Comparisons of aggregate claim numbers and amounts: a study of heterogeneity

In this paper, we investigate how the heterogeneity among occurrence probabilities and claim severities affects the aggregate claim numbers and aggregate claim amount for an insurance portfolio. We show that higher heterogeneity (and dependence) among occurrence probabilities results in both smaller aggregate claim numbers and aggregate claim amount in the sense of the mean residual lifetime order. We also prove that as the heterogeneity among the claims increases, the aggregate claim amount increases in the sense of the usual stochastic order when the vector of occurrence probabilities is left tail weakly stochastic arrangement increasing. These theoretical findings are applied to (i) study ordering properties of convolutions of binomial random variables, (ii) provide upper bounds for the mean residual lifetime functions of the aggregate claim numbers and amount, and (iii) compare stop-loss premiums and risk capital of different insurance portfolios.     

关于Lucas数的一类行列式的计算

研究了一类由Lucas数组成的特殊行列式D(nm,k,l)的计算问题,并给出了一个有趣的恒等式。     

LARGE PORTFOLIO ASYMPTOTICS FOR LOSS FROM DEFAULT

We prove a law of large numbers for the loss from default and use it for approximating the distribution of the loss from default in large, potentially heterogeneous portfolios. The density of the limiting measure is shown to solve a nonlinear stochastic partial differential equation, and certain moments of the limiting measure are shown to satisfy an infinite system of stochastic differential equations. The solution to this system leads to the distribution of the limiting portfolio loss, which we propose as an approximation to the loss distribution for a large portfolio. Numerical tests illustrate the accuracy of the approximation, and highlight its computational advantages over a direct Monte Carlo simulation of the original stochastic system.     

Weak measurability and characterizations of risk

Summary. In the context of a continuum of random variables, arising, for example, as rates of return in financial markets with a continuum of assets, or as individual responses in games with a continuum of players, an important economic issue is to show how idiosyncratic risk can be removed through some device of aggregation or diversification when such risk is explicitly introduced into the model. In this paper, we use recent work of Al-Najjar [1] as a general backdrop to provide a review of the basic issues involved when the continuum is formulated as the Lebesgue interval. We present two examples to argue that the fundamental problem of the non-measurability of sample functions, originally identified by Doob, and further elaborated by Feldman, Gilles and Judd in the economic literature, simply cannot be bypassed by reinterpretations of standard results. We also provide an equivalence result in the spirit of Al-Najjar's efforts; but argue that this elementary result does not go beyond the standard law of large numbers for a sequence of real-valued iid random variables, and as such, is incapable of yielding anything of substantive economic interest beyond this law. Received: April 23, 1998; revised version: April 28, 1998     

第二类stirling数的又一个恒等式的简化

第二类stirling数是分配问题中的最关键数,当n与r很大时stirling数的计算极为繁琐.给出并证明了当n≥12的第二类stirling数S(n,n-6)的恒等式,从而将n≥8的第二类stirling数S(n,n-4)的计算在文献[1]的基础上向前推进了一步.     

基于熵权法和MADM的电力客户信用风险评价

电力客户的信用风险评价是典型的多属性决策问题,决策者往往很难对每个评价指标赋予一个确定数值,但凭借经验可以给出大致范围。有鉴于此,论文在描述电力客户的各个属性值时采用了区间数的表示形式,并运用熵权法确定出各评价指标的权重,最后计算各个电力客户的综合评价值并进行排序优选。实例研究结果表明这种方法是科学实用的电力客户信用评价比较方法。