Testing Alternative Regression Frameworks for Predictive Modeling of Health Care Costs

Predictive models of health care costs have become mainstream in much health care actuarial work. The Affordable Care Act requires the use of predictive modeling-based risk-adjuster models to transfer revenue between different health exchange participants. Although the predictive accuracy of these models has been investigated in a number of studies, the accuracy and use of models for applications other than risk adjustment have not been the subject of much investigation. We investigate predictive modeling of future health care costs using several statistical techniques. Our analysis was performed based on a dataset of 30,000 insureds containing claims information from two contiguous years. The dataset contains more than 100 covariates for each insured, including detailed breakdown of past costs and causes encoded via coexisting condition flags. We discuss statistical models for the relationship between next-year costs and medical and cost information to predict the mean and quantiles of future cost, ranking risks and identifying most predictive covariates. A comparison of multiple models is presented, including (in addition to the traditional linear regression model underlying risk adjusters) Lasso GLM, multivariate adaptive regression splines, random forests, decision trees, and boosted trees. A detailed performance analysis shows that the traditional regression approach does not perform well and that more accurate models are possible.     

Performance of Moving Average Trading Rules in a Volatile Stock Market: The Russian Evidence

This article examines the profitability of dual moving average crossover (DMAC) trading strategies in the Russian stock market over the 2003–12 period. It contributes to the existing technical analysis (TA) literature by testing, for the first time, the applicability of ordered weighted moving averages (OWMA) as an alternative calculation basis for determining DMACs. In addition, this article provides the first comprehensive performance comparison of DMAC trading rules in the stock market that is known as one of the most volatile markets in the world. The results show that the best trading strategies of the in-sample period can also outperform their benchmark portfolio during the subsequent out-of-sample period. Moreover, the outperformance of the best DMAC strategies is mostly attributable to their superior performance during bearish periods and, particularly, during stock market crashes.     

Investigating Adoption of Free Beta Applications in a Platform‐Based Business Ecosystem

Planning new product development (NPD) activities is becoming increasingly difficult, as contemporary businesses compete at the level of business ecosystems in addition to the firm‐level product‐market competition. These business ecosystems are built around platforms interlinking suppliers, complementors, distributors, developers, etc. together. The competitiveness of these ecosystems relies on members utilizing the shared platform for their own performance improvement, especially in terms of developing new valuable offerings for end users. Therefore, managing the development of the platform‐based applications and gaining timely end‐user input for NPD are of vital importance both to the ecosystem as a whole and to the developers. Subsequently, to succeed in NPD planning developers utilizing beta testing need a thorough understanding of the adoption dynamics of beta products. Developers need to plan for example resource allocation; development costs; and timing of commercial, end‐product launches. Therefore, the anticipation of the adoption dynamics of beta products emerges as an important antecedent in planning NPD activities when beta testing is used for gaining end‐user input to the NPD process. Consequently, we investigate how free beta software products that are built upon software platforms diffuse among their end users in a cocreation community. We specifically study whether the adoption of these beta products follows Bass or Gompertz model dynamics used in the previous literature when modeling the adoption of stand‐alone products. Further, we also investigate the forecasting abilities of these two models. Our results show that the adoption dynamics of free beta products in a cocreation community follow Gompertz's model rather than the Bass model. Additionally, we find that the Gompertz model performs better than the Bass model in forecasting both short and long out‐of‐sample time periods. We further discuss the managerial and research implications of our study.     

Behavioral theories and the pricing of IPOs’ discretionary current accruals

The main purpose of this paper is to provide additional evidence about the effect of discretionary current accruals on the pricing of IPOs. This paper seeks to discriminate between two alternative explanations for the prior findings: (1) behavioral biases coupled with limited arbitrage; and (2) the sample- and period-specific nature of the results in the prior literature. The IPOs from 1962 to 1998 were used to obtain the following results. First, there was not a negative association observed between discretionary current accruals and subsequent price performance for the 1926–1971 period. Second, analysis reveals that the pattern of cross-sectional evidence is inconsistent with the predictions made by behavioral theories. Third, in the 1972–1998 period, evidence of predictable negative performance attributable to IPO discretionary current accruals is limited to NASDAQ firms. These findings are difficult to reconcile with the explanation of behavioral biases coupled with limited arbitrage.     

Monte Carlo theoretical trials of methods for assessing statistical significance for differences between adjusted odds ratios

Odds are generally defined as the number of successes divided by the number of failures in a given number of trials. An odds ratio is the ratio of one odds divided by another. Odds ratios can be adjusted to reflect associations with the outcome independently of the influence of associations with other variables. These are adjusted odds ratios. There are several well known methods for comparing odds ratios and testing for statistically significant differences between them. Analogous methods for adjusted odds ratios are not well known or well documented. One method for comparing adjusted odds ratios is explained by Hosmer and Lemeshow (Applied logistic regression, 2000). This method is used for the odds ratios for two variables from the same data set. The purpose of this analysis was to apply this method to a different situation: comparing odds ratios for the same variable from two different data sets. Monte Carlo trials were used to assess the performance of the method and these indicated the method performed well.     

Intergroup contact and reduction of explicit and implicit prejudice toward immigrants: a study with Italian businessmen owning small and medium enterprises

A field study was conducted to test the effectiveness of intergroup contact (Allport, The nature of prejudice, 1954) as a predictor of explicit and implicit attitudes toward immigrants and to examine the processes driving its effects. Participants were Italian businessmen owning small and medium enterprises in Northern Italy who had daily contact with their immigrant workers. We tested a model in which contact ameliorated explicit attitudes, measured as support for social policies toward immigration, through reduced negative outgroup stereotypes. Furthermore, we predicted that contact would have a direct, unmediated effect on improved implicit attitudes toward immigrants, assessed with an Implicit Association Test (Greenwald et al., J Personal Soc Psychol 74:1464–1480, 1998). The results were fully consistent with predictions, thus providing strong support for the contact hypothesis at both an explicit and at an implicit level. The lack of correlation between explicit and implicit attitudes supports dual-process models, suggesting that the two types of attitudes are formed through different processes. The theoretical and practical implications of the findings are discussed.     

Organizational climate for innovation and creative teaching in urban and rural schools

Due to the impact of knowledge-based economies, all countries strive to foster creative education. Research has demonstrated that creativity is influenced both by individual characteristics and by the environment. Previous research examining creative teaching by teachers in Taiwan has typically focused on the relationships between creative teaching and innovative personal characteristics, school leaders’ behaviors, and internal motivation. The purpose of this study was to move beyond prior research to investigate the relationship between creative teaching behaviors and innovation-fostering elements of the organizational climate in schools. In addition, we examined the impact on teacher creativity of urban versus rural school location.     

Time-varying persistence in US inflation

The persistence property of inflation is an important issue not only for economists, but especially for central banks, given that the degree of inflation persistence determines the extent to which central banks can control inflation. Further, not only is it the level of inflation persistence that is important in economic analyses, but also the question of whether the persistence varies over time, for instance, across business cycle phases, is equally pertinent, since assuming constant persistence across states of the economy is sure to lead to misguided policy decisions. Against this backdrop, we extend the literature on long-memory models of inflation persistence for the US economy over the monthly period of 1920:1–2014:5, by developing an autoregressive fractionally integrated moving-average-generalized autoregressive conditional heteroskedastic model with a time-varying memory coefficient which varies across expansions and recessions. In sum, we find that inflation persistence does vary across recessions and expansions, with it being significantly higher in the former than in the latter. As an aside, we also show that persistence of inflation volatility is higher during expansions than in recessions. Understandably, our results have important policy implications.     

Steuerpolitik und Wirtschaftswachstum

The design of the tax system matters for economic growth. During times of economic crisis, tax instruments such as temporary tax cuts can be used to soften adverse effects on the economy by stimulating private and corporate spending. However, empirical evidence suggests that the overall impact of short term tax policies is limited. In the long run, the structure of the tax system is essential to building up an investment friendly and innovation-stimulating environment, which will promote sustainable economic growth.