This paper characterizes the rate of convergence of discrete‐time multinomial option prices. We show that the rate of convergence depends on the smoothness of option payoff functions, and is much lower than commonly believed because option payoff functions are often of all‐or‐nothing type and are not continuously differentiable. To improve the accuracy, we propose two simple methods, an adjustment of the discrete‐time solution prior to maturity and smoothing of the payoff function, which yield solutions that converge to their continuous‐time limit at the maximum possible rate enjoyed by smooth payoff functions. We also propose an intuitive approach that systematically derives multinomial models by matching the moments of a normal distribution. A highly accurate trinomial model also is provided for interest rate derivatives. Numerical examples are carried out to show that the proposed methods yield fast and accurate results. 相似文献
This paper analyzes a simple model that captures the relationship between institutional quality, the shadow economy, and corruption.
It shows that an improvement in institutional quality reduces the shadow economy and affects the corruption market. The exact
relationship between corruption and institutional quality is, however, ambiguous and depends on the relative effectiveness
of institutional quality in the shadow and corruption markets. The analytics also show that the shadow economy and corruption
are substitutes. The predictions of the model are empirically tested and confirmed. 相似文献
In a previous article the authors provided an introduction to using the internet as a resource for business ethics. In this sequel they look at newsgroups and chatrooms, and conclude by looking at the websites of Shell and a Shell critic on the controversial ethical aspects of its corporate policy and behaviour. Ben Fairweather is a Research Fellow, and Steve Dixon is Webmaster, at the Centre for Computing and Social Responsibility, De Montfort University, The Gateway, Leicester LEl 9BH, England (email: ccsr@dmu.ac.uk) (website http://www.ccsr.cms.dmu.ac.uk/). 相似文献
This paper reexamines the determinants of the number of analysts following a firm using econometric models based on count distributions. We replicate Bhushan's (1989) analyst-following study to demonstrate the effects of using count-data econometrics, in lieu of OLS, in studying phenomena where the dependent variable ranges among nonnegative integers. In contrast with the original paper, our findings indicate the number of institutional investors is inversely related with analyst following. We also provide econometric evidence to support the preferred use of the negative binomial model in estimating cross-sectional, analyst-following regressions. 相似文献
Public services in the UK are increasingly expected to account for their outputs and performance. This article describes a retrospective evaluation of the benefits from the R&D funded by a regional office of the NHS Executive. The methods adopted enabled the various elements of the region's R&D portfolio to be examined and provided a basis for the development of a plan for regular monitoring. The proposals for implementation are now also feeding into a debate as to how health services R&D might best be monitored nationally in a way that is compatible with the norms and practices of research in other contexts. 相似文献
Income smoothing, as defined in Statistical Activity Cost Theory (SACT), is the rational statistical adjustment of periodic accounting earnings to reduce their time volatility around average long-term profit per period. This article demonstrates how overhead cost allocations can be applied to smooth accounting earnings optimally in accordance with this definition. Such an approach parallels earlier work, such as that by Lane and Willett (1997 , 1999 ), in which a depreciation formula was derived and applied for this purpose. In particular, it is shown that, to realize an income smoothing effect in profit making firms, the usual optimal strategy is to over-allocate costs, giving support to the accounting principle of conservatism. 相似文献
Telaprevir (TVR,T) and boceprevir (BOC,B) are direct-acting antivirals (DAAs) used for the treatment of chronic genotype 1 hepatitis C virus (HCV) infection. This analysis evaluated the cost-effectiveness of TVR combined with pegylated interferon (Peg-IFN) alfa-2a plus ribavirin (RBV) compared with Peg-IFN alfa-2a and RBV (PR) alone or BOC plus Peg-IFN alfa-2b and RBV in treatment-experienced patients.
Methods:
A Markov cohort model of chronic genotype 1 HCV disease progression reflected the pathway of experienced patients retreated with DAA therapy. The population was stratified by previous response to treatment (i.e., previous relapsers, partial responders, and null responders). Sustained virologic response (SVR) rates were derived from a mixed-treatment comparison that included results from separate Phase III trials of TVR and BOC. Incremental cost per life year (LY) gained and quality-adjusted-life-year (QALY) gained were computed at lifetime, adopting the NHS perspective. Costs and health outcomes were discounted at 3.5%. Uncertainty was assessed using deterministic and probabilistic sensitivity analyses. Sub-group analyses were carried out by interleukin (IL)-28B genotype.
Results:
Higher costs and improved outcomes were associated with T/PR relative to PR alone for all experienced patients (ICER of £6079). T/PR was cost-effective for each sub-group population with high SVR advantage in relapsers (ICER of £2658 vs £7593 and £20,875 for partial and null responders). T/PR remained cost-effective regardless of IL-28B sub-type. Compared to B/PR, T/PR prolonged QALYs by 0.57 and reduced lifetime costs by £13,960 for relapsers. For partial responders T/PR was less costly but less efficacious than B/PR, equating to an ICER of £128,117 per QALY gained.
Limitations:
No head-to-head trial provides direct evidence of better efficacy of T/PR vs B/PR.
Conclusion:
T/PR is cost-effective compared with PR alone in experienced patients regardless of treatment history and IL-28B genotype. Compared to B/PR, T/PR is always cost-saving but only more effective in relapsers. 相似文献
This article reviews the rapidly growing literature on structural models of complementary choices. It discusses recent modeling developments and identifies promising areas for future research. 相似文献
Globalization has motivated managers and scholars in the tourism industry to focus more attention on the problems and characteristics of the cross-cultural service encounter. During these interactions, differing cultural norms and values often create misunderstanding and conflict, which can result in an unhappy customer, a frustrated service provider and lost business. Therefore, the focus of this study was to analyze the effect of intercultural sensitivity on tourism employee performance in cross-cultural service encounters in three similar, but distinct service-dependent markets: the Hawaiian Islands, Greater London (UK) and the state of Florida. The results indicate that tourism employees with high intercultural sensitivity generally scored significantly (p < 0.05) higher than employees with low intercultural sensitivity in terms of service attentiveness, revenue contribution, interpersonal skills, job satisfaction and social satisfaction as they relate to cross-cultural encounters. There was no significant difference in results for motivation to work, tenure (years at present organization) and primary rewards (compensation, recognition, etc.). Implications of the findings are discussed. 相似文献