We examine and compare a large number of generalized autoregressive conditional heteroskedastic (GARCH) and stochastic volatility (SV) models using series of Bitcoin and Litecoin price returns to assess the model fit for dynamics of these cryptocurrency price returns series. The various models examined include the standard GARCH(1,1) and SV with an AR(1) log-volatility process, as well as more flexible models with jumps, volatility in mean, leverage effects, t-distributed and moving average innovations. We report that the best model for Bitcoin is SV-t while it is GARCH-t for Litecoin. Overall, the t-class of models performs better than other classes for both cryptocurrencies. For Bitcoin, the SV models consistently outperform the GARCH models and the same holds true for Litecoin in most cases. Finally, the comparison of GARCH models with GARCH-GJR models reveals that the leverage effect is not significant for cryptocurrencies, suggesting that these do not behave like stock prices. 相似文献
This article studies the consequences of fixed commissions and low entry barriers in Greater Boston's real estate brokerage industry from 1998–2007. We find that agent entry reduces average service quality and use a dynamic empirical model to study the inefficiency in the current market structure. To accommodate a large state space, we approximate the value function using sieves and impose the Bellman equation as an equilibrium constraint. Our results suggest that a 50% cut in commissions would result in 40% fewer agents, social savings that amount to 23% of industry revenue, and 73% more transactions for the average agent. 相似文献
ABSTRACT This paper proposes an integrative view of the marketing concept (i.e., the ability to understand and satisfy customers) and examines its prevalence and effect on competitiveness in organizations operating in an isolated and less economically developed country. The marketing concept manifests as marketing expertise, market orientation, and externally directed organizational values. Based on a sample of 86 firms operating in Fiji, the results indicate that these three mechanisms promote organizational competitiveness, thus supporting the universality of the marketing concept. These findings confirm the important role of the marketing concept in the competitiveness of firms in a less developed economy. 相似文献
We examine the co-movement in daily returns of USD–INR, EUR–INR, GBP–INR, and JPY–INR currency pair futures contracts traded on the National Stock Exchange of India (NSE) using the wavelet cohesion approach. This study contributes to the literature by examining the scantly studied area of co-movement in exchange rates and using the wavelet approach, which allows us to analyse time–frequency-wise co-movement of the time series. The empirical results indicate that the currency futures markets are nearly perfectly integrated in the long run (monthly, quarterly and biannual scales) offering little potential gains from international portfolio diversification. The discrepancies between currency futures markets are small and almost fade away within 3–6 months. Moreover, international currency diversification might offer relatively higher potential gains at intraweek, weekly, and fortnightly time horizons owing to lower correlations among the currencies under consideration. Finally, our multiple-wavelet correlation and cross-correlation analysis shows that GBP acts as a potential leader/follower across scales. The results of our analysis indicate the dynamic pattern of co-movement among the major currency futures contracts, which provides several implications for portfolio managers and international investors participating in the Indian market. 相似文献
Objective: Omalizumab add-on to standard-of-care therapy has proven to be efficacious in severe asthma patients for whom exacerbations cannot be controlled otherwise. Moreover, evidence from different healthcare settings suggests reduced healthcare resource utilization with omalizumab. Based on these findings, this study aimed to assess the cost-effectiveness of the addition of omalizumab to standard-of-care therapy in patients with uncontrolled severe allergic asthma in a Brazilian healthcare setting.
Methods: A previously published Markov model was adapted using Brazil-specific unit costs to compare the costs and outcomes of the addition of omalizumab to standard-of-care therapy vs standard-of-care therapy alone. Model inputs were largely based on the eXpeRience study. Costs and health outcomes were calculated for lifetime-years and were annually discounted at 5%. Both one-way and probabilistic sensitivity analyses were performed.
Results: An additional cost of R$280,400 for 5.20 additional quality-adjusted life-years was estimated with the addition of omalizumab to standard-of-care therapy, resulting in an incremental cost-effectiveness ratio of R$53,890. One-way sensitivity analysis indicated that discount rates, standard-of-care therapy exacerbation rates, and exacerbation-related mortality rates had the largest impact on incremental cost-effectiveness ratios.
Limitations: Assumptions of lifetime treatment adherence and rate of future exacerbations, independent of previous events, might affect the findings. The lack of Brazilian patients in the eXpeRience study may affect the findings, although sample size and baseline characteristics suggest that the modeled population closely resembles Brazilian severe allergic asthma patients.
Conclusion: Results indicate that omalizumab as an add-on therapy is more cost-effective than standard-of-care therapy alone for Brazilian patients with uncontrolled severe allergic asthma, based on the World Health Organization’s cost-effectiveness threshold of up to 3-times the gross domestic product. 相似文献
Co-opetition, or simultaneous competition and cooperation, in the supply chain management literature has been treated as a dyadic relational phenomenon where the buyer's strategy is considered to be the primary driver. In this paper, we move beyond the dyadic view and propose a theory of co-opetition in supply networks. We argue that as firms within a supply network interact over time to access, share, and transform resources, new ties between firms are formed and existing ties dissolve, giving rise to co-opetition dynamics at the network level. Taking a configurational approach, we employ the inter-related dimensions of ties between firm, firm-level task, network-level objective, and governance to specify four practical supply network archetypes that cover a wide range of economic activities. We then explain how coopetitive relationships may evolve in these supply network archetypes. Specifically, we discuss how relationships form or dissolve in these archetypes and how local structural changes lead to co-opetition dynamics at the network level. We also discuss the implications of such dynamics from a managerial perspective. 相似文献
Since the Sarbanes-Oxley Act was enacted in U.S., there has been a general tendency to globally harmonize regulations and practices of board governance. The purpose of this study is to compare among countries how well the board of directors constrains earnings management. Using a sample of firms from 23 countries, we document some evidence that higher outside directorship on the board is associated with lower earnings management in the international context. We also find that there is no significant difference in the effectiveness of board outside directorship in constraining earnings management between high and low investor protection countries. Our findings mitigate a concern that harmonized corporate governance in low investor protection countries may not work. 相似文献
We investigate how recent advances in information technology and telecommunications have led to real-time monitoring of processes at the site of the provider by a buyer located across the globe. We construct a game-theoretic model of the dynamics of the buyer–supplier interaction in the presence of moral hazard and incomplete contracting. We derive the Minimum Quality Threshold (MQT) below which the provider's output will certainly be inspected. Our findings show that the buyer can pick a level of monitoring and thereby force the provider to exceed the quality level of the MQT in output quality and avoid costly and wasteful inspection. Finally, our model explains why the production of processes that are complex and more prone to errors are actually monitored less by the buyers. We furnish the results of a comprehensive, multi-year, multi-country survey of the efficacy of monitoring in off-shore outsourcing projects and demonstrate strong empirical support for the findings of the model. 相似文献
Costly punishment can facilitate cooperation in public-goods games, as human subjects will incur costs to punish non-cooperators even in settings where it is unlikely that they will face the same opponents again. Understanding when and why it occurs is important both for the design of economic institutions and for modeling the evolution of cooperation. Our experiment shows that subjects will engage in costly punishment even when it will not be observed until the end of the session, which supports the view that agents enjoy punishment. Moreover, players continue to cooperate when punishment is unobserved, perhaps because they (correctly) anticipate that shirkers will be punished: Fear of punishment can be as effective at promoting contributions as punishment itself. 相似文献