Finite sample properties of estimators for autoregressive moving average models

We analyze by simulation the properties of three estimators frequently used in the analysis of autoregressive moving average time series models for both nonseasonal and seasonal data. The estimators considered are exact maximum likelihood, exact least squares and conditional least squares. For samples of the size commonly found in economic applications, the estimators are compared in terms of bias, mean squared error, and predictive ability. The reliability of the usually calculated confidence intervals is assessed for the maximum likelihood estimator.     

Television-Induced Tourism: Evidence from Croatia

Atlantic Economic Journal - This paper analyzes the extent to which the filming of the popular television show Game of Thrones affected tourism in the Croatian city of Dubrovnik. Using monthly data...     

Shareholder Primacy,Corporate Social Responsibility,and the Role of Business Schools

This paper examines the shareholder primacy norm (SPN) as a widely acknowledged impediment to corporate social responsibility and explores the role of business schools in promoting the SPN but also potentially as an avenue for change by addressing misconceptions about shareholder primacy and the purpose of business. We start by explaining the SPN and then review its status under US and UK laws and show that it is not a likely legal requirement, at least under the guise of shareholder value maximization. This is in contrast to the common assertion that managers are legally constrained from addressing CSR issues if doing so is inconsistent with the economic interests of shareholders. Nonetheless, while the SPN might be muted as a legal norm, we show that it is certainly evident as a social norm among managers and in business schools—reflective, in part, of the sole voting rights of shareholders on corporate boards and of the dominance of shareholder theory—and justifiably so in the view of many managers and business academics. We argue that this view is misguided, not least when associated with claims of a purported legally enforceable requirement to maximize shareholder value. We propose two ways by which the influence of the SPN among managers might be attenuated: extending fiduciary duties of executives to non-shareholder stakeholders and changes in business school teaching such that it covers a plurality of conceptions of the purpose of the corporation.     

Free-Agency and the Competitiveness of Major League Baseball

I investigate whether the removal of the reserve clause in professional baseball affected the competitive nature of the industry in the context of whether the distribution of team wins has been affected by free-agency. Unlike previous studies which use the standard deviation of winning percentage, I use a more sensitive measure of parity. I calculate the deviations of the Herfindahl-Hirschman Index of team wins from the competitive ideal during 1920 to 1996 and relate them to player-talent distribution and structural changes in the industry. I isolate the structural effect of free-agency and find that it has adversely affected the parity of the American League but that it has had no statistical influence on the parity of the National League.     

New low-frequency spread measures

I develop new spread proxies that pick up on three attributes of the low-frequency (daily) data: (1) price clustering, (2) serial price covariance accounting for midpoint prices on no-trade days, and (3) the quoted spread that is available on no-trade days. I develop and empirically test two different approaches: an integrated model and combined models. I test both new and existing low-frequency spread measures relative to two high-frequency benchmarks (percent effective spread and percent quoted spread) on three performance dimensions: (1) higher individual firm correlation with the benchmarks, (2) higher portfolio correlation with the benchmarks, and (3) lower distance relative to the benchmarks. I find that on all three performance dimensions the new integrated model and the new combined model do significantly better than existing low-frequency spread proxies.     

Cost-effectiveness of rivaroxaban compared with enoxaparin plus a vitamin K antagonist for the treatment of venous thromboembolism

Background:

Venous thromboembolism (VTE), comprised of deep vein thrombosis (DVT) and pulmonary embolism (PE), is commonly treated with a low-molecular-weight heparin such as enoxaparin plus a vitamin K antagonist (VKA) to prevent recurrence. Administration of enoxaparin?+?VKA is hampered by complexities of laboratory monitoring and frequent dose adjustments. Rivaroxaban, an orally administered anticoagulant, has been compared with enoxaparin?+?VKA in the EINSTEIN trials. The objective was to evaluate the cost-effectiveness of rivaroxaban compared with enoxaparin?+?VKA as anticoagulation treatment for acute, symptomatic, objectively-confirmed DVT or PE.

Methods:

A Markov model was built to evaluate the costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios associated with rivaroxaban compared to enoxaparin?+?VKA in adult patients treated for acute DVT or PE. All patients entered the model in the ‘on-treatment’ state upon commencement of oral rivaroxaban or enoxaparin?+?VKA for 3, 6, or 12 months. Transition probabilities were obtained from the EINSTEIN trials during treatment and published literature after treatment. A 3-month cycle length, US payer perspective ($2012), 5-year time horizon and a 3% annual discount rate were used.

Results:

Treatment with rivaroxaban cost $2,448 per-patient less and was associated with 0.0058 more QALYs compared with enoxaparin?+?VKA, making it a dominant economic strategy. Upon one-way sensitivity analysis, the model’s results were sensitive to the reduction in index VTE hospitalization length-of-stay associated with rivaroxaban compared with enoxaparin?+?VKA. At a willingness-to-pay threshold of $50,000/QALY, probabilistic sensitivity analysis showed rivaroxaban to be cost-effective compared with enoxaparin?+?VKA approximately 76% of the time.

Limitations:

The model did not account for the benefits associated with an oral and minimally invasive administration of rivaroxaban. ‘Real-world’ applicability is limited because data from the EINSTEIN trials were used in the model. Also, resource utilization and costs were based on the US healthcare system.

Conclusion:

Rivaroxaban is a cost-effective option for anticoagulation treatment of acute VTE patients.