Spatial Interaction,Spatial Multipliers and Hospital Competition

The hospital competition literature shows that estimates of the effect of local market structure (concentration) on pricing (competition) are sensitive to geographic market definition. Our spatial lag model approach effects smoothing of the explanatory variables across the discrete market boundaries, resulting in robust estimates of the impact of market structure on hospital pricing, which can be used to estimate the full effect of changes in prices inclusive of spillovers that cascade through the neighboring hospital markets. The full amount, generated by the spatial multiplier effect, is a robust estimate of the impacts of market factors on hospital competition. We contrast ordinary least squares and spatial lag estimates to demonstrate the importance of robust estimation in analysis of hospital market competition. In markets where concentration is relatively high before a proposed merger, we demonstrate that Ordinary Least Squares (OLS) can lead to the wrong policy conclusion while the more conservative lag estimates do not.     

An empirical analysis of national and local advertising effect on price elasticity

This paper investigates the interaction effect of advertising and price on the market share of a consumer nondurable product. We postulate a model in which local advertising is thought to primarily affect the consumers' purchase by making the demand more price sensitive, and national advertising to affect the consumers' preference, thus making the demand less price sensitive. Moreover, we hypothesize that local advertising interaction will have more immediate effect, while national advertising interaction will have longer term interaction effects. We apply these ideas empirically, and find support for our hypotheses. Thus, the interaction effect of advertising and price can be characterized by both increased and decreased price sensitivity, depending on the type of advertising. Moreover, these effects may be present simultaneously for the same product.     

地方财政支出的空间外部效应研究

财政行为的空间外部性是应用公共经济学的重要研究课题。目前，国内既有文献多是集中于对税收竞争的考察。对于地方财政支出空间外部效应的研究还非常缺乏。依据Case和Rosen（1993）的思路，本文采用空间计量方法对我国地方财政支出的空间外部性进行了经验研究。结果表明，总体上看，地方财政支出具有显著的正外部效应。但进一步对建设支出和教育科技支出这两个细分项目的分析则显示，后者并未表现出显著的空间外部效应。上述结论的得出为最优分权规模的确定提供了一个新的观察视角。     

Estimating the long-term effects of advertising on sales: a co-integration perspective

Co-integration econometrics have important theoretical advantages over more traditional approaches to estimating the long-term effects of one variable on another. When advertising and sales data are co-integrated, adaptations of common econometric procedures may be used to estimate the long-term effects directly rather than inferring them from short-term relationships. This paper presents a method for detecting and estimating co-integrating relationships using ordinary least-squares regression procedures. The method is illustrated with the well-known Lydia Pinkham data from 1907 through to 1961. The results show that there was a strong positive relationship between Lydia Pinkham advertising and sales in the long-term. Implications of the method and findings are discussed.     

Price transmission between products at different stages of manufacturing in forest industries

The theory of demand and supply implies a positive relationship, or “price transmission” between the prices of products at different stages of manufacturing. This relationship was investigated with quarterly prices of softwood stumpage in the US South, and national prices of forest products, from 1977 to 2002. All prices, net of inflation, were found to be nonstationary and there was no evidence of co-integration between prices. Vector autogressive models, augmented by Granger causality tests and multiplier analysis showed that there was a one-to-one permanent positive response of the southern sawtimber stumpage price to a permanent change in the national lumber price. There was also a one-third permanent positive response of the national paper price to a permanent change in the national pulp price. There was no relation between regional pulpwood prices and national pulp or paper prices. When price transmission was significant, the full adjustment took about 2 years.     

关于提高本科计量经济学教学质量的思考

当前国内计量经济学教学中普遍存在的突出问题是,教学目标和内容定位不明确,理论教学与案例、实验教学相脱节,重理论教学而轻实际应用.造成这些问题的原因主要是,课程设置和安排不合理,教师素质与教学水平不高,缺乏高水平的教材.必须从提高教师素质,编写高水平教材,改进教学方法,以及改善教学条件等方面采取措施来提高教学质量.     

The endo–exo problem in high frequency financial price fluctuations and rejecting criticality

The endo–exo problem lies at the heart of statistical identification in many fields of science, and is often plagued by spurious strong-and-long memory due to improper treatment of trends, shocks and shifts in the data. A class of models that has shown to be useful in discerning exogenous and endogenous activity is the Hawkes process. This class of point processes has enjoyed great recent popularity and rapid development within the quantitative finance literature, with particular focus on the study of market microstructure and high frequency price fluctuations. We show that there are important lessons from older fields like time series and econometrics that should also be applied in financial point process modelling. In particular, we emphasize the importance of appropriately treating trends and shocks for the identification of the strength and length of memory in the system. We exploit the powerful Expectation Maximization algorithm and objective statistical criteria (BIC) to select the flexibility of the deterministic background intensity. With these methods, we strongly reject the hypothesis that the considered financial markets are critical at univariate and bivariate microstructural levels.     

Network concentration and airport congestion in a post de-regulation context: A case study of Brazil 2000–2010

This paper empirically investigates the main drivers of airline network concentration in an air transport market subject to rapid growth. We consider the Brazilian air transport industry of the 2000s, in which network concentration rapidly increased and was followed by a period of massive flight delays and cancelations, which resulted in the “big blackout” of 2006–2007. We develop an econometric model of network concentration, accounting for demand, cost and competition variables that may affect the propensity of carriers to concentrate flights and passenger connections on a few airports of a network. The main focus of the paper is on the relation between networks leading to the problems of the blackout episode. We investigate the dynamic pattern of the evolution of concentration before and after the abnormal period of operations and find that concentration began to rise at least six quarters before, and persisted at a high level until two quarters after the blackout – and then plunged steeply toward the end of the decade. We believe that our analysis contributes to an improved understanding of the behavior of air transport systems subject to network concentration and congestion. With respect to methodology, we suggest and employ the use of alternative measures of network concentration to check the robustness and validity of our results.     

Does board gender diversity influence firm profitability? A control function approach

We investigate the relation between board gender diversity and firm profitability using the control function (CF) approach recently suggested by Wooldridge (2015). The CF method takes account of the problem of endogenous explanatory variables that have potential to bias the results. Using a sample of firms that made up the S&P 500 over the period 2004–2015, we find that the presence of women on corporate boards (measured either by the percentage of female directors on corporate boards or the Blau index of heterogeneity) has a positive and significant (at the 1% level) effect on firm profitability (measured by the return on assets). We compare our results to more traditional approaches (such as pooled OLS or the fixed-effects model). Through this study, we shed light on the effect of women on corporate boards on firm performance, as it is still a controversial issue (Post and Byron, 2015).