Model selection in random effects models for directed graphs using approximated Bayes factors

With the development of an MCMC algorithm, Bayesian model selection for the p ₂ model for directed graphs has become possible. This paper presents an empirical exploration in using approximate Bayes factors for model selection. For a social network of Dutch secondary school pupils from different ethnic backgrounds it is investigated whether pupils report that they receive more emotional support from within their own ethnic group. Approximated Bayes factors seem to work, but considerable margins of error have to be reckoned with.     

一种新的尝试:利用JXTA P2P技术搭建自主计算平台

自主计算的目标是为了简化日益繁杂的IT设施管理,从而降低成本、提升效率。本文分析了自主计算的基本特点和需求,结合P2P计算的特性,以P2P的角度重新审视构建自主计算全局架构的方法,阐述了用JXTA实现自主计算自主管理器的思想。     

Observability and incentive in organizations

The paper shows that producer-owned firms are more efficient in quality provision than investor-owned firms if input quality is observable, while they are less efficient when the input quality is unobservable and the size of the organization is large.     

Pace of work and piece rates

Using cross-industry survey data, I examine how the determinants of the pace of work affect the probability of using piece rates. Internal determinants raise the likelihood of piece rates, while response to external needs lowers the probability.     

Evaluation of the long-term cost-effectiveness of IDegLira versus liraglutide added to basal insulin for patients with type 2 diabetes failing to achieve glycemic control on basal insulin in the USA

Background and aims: IDegLira, a fixed ratio combination of insulin degludec and glucagon-like peptide-1 receptor agonist liraglutide, utilizes the complementary mechanisms of action of these two agents to improve glycemic control with low risk of hypoglycemia and avoidance of weight gain. The aim of the present analysis was to assess the long-term cost-effectiveness of IDegLira vs liraglutide added to basal insulin, for patients with type 2 diabetes not achieving glycemic control on basal insulin in the US setting.

Methods: Projections of lifetime costs and clinical outcomes were made using the IMS CORE Diabetes Model. Treatment effect data for patients receiving IDegLira and liraglutide added to basal insulin were modeled based on the outcomes of a published indirect comparison, as no head-to-head clinical trial data is currently available. Costs were accounted in 2015?US dollars ($) from a healthcare payer perspective.

Results: IDegLira was associated with small improvements in quality-adjusted life expectancy compared with liraglutide added to basal insulin (8.94 vs 8.91 discounted quality-adjusted life years [QALYs]). The key driver of improved clinical outcomes was the greater reduction in glycated hemoglobin associated with IDegLira. IDegLira was associated with mean costs savings of $17,687 over patient lifetimes vs liraglutide added to basal insulin, resulting from lower treatment costs and cost savings as a result of complications avoided.

Conclusions: The present long-term modeling analysis found that IDegLira was dominant vs liraglutide added to basal insulin for patients with type 2 diabetes failing to achieve glycemic control on basal insulin in the US, improving clinical outcomes and reducing direct costs.     

Economic modelling of costs associated with outcomes reported for type 2 diabetes mellitus (T2DM) patients in the CANVAS and EMPA-REG cardiovascular outcomes trials

Aims: To model direct medical costs associated with reductions in cardiovascular disease (CVD) events in T2DM patients reported in the CANVAS and EMPA-REG trials, which assessed the cardiovascular safety of canagliflozin and empagliflozin, respectively.

Materials and methods: Costs were modeled from a US managed care organization (MCO) perspective for the CVD outcomes included in both trials: three-point major adverse cardiovascular event (MACE) and its components (cardiovascular-related death, nonfatal myocardial infarction, nonfatal stroke), as well as heart failure requiring hospitalization. The rate of CVD events averted (difference between study drug and placebo) was projected to the portion of an MCO T2DM population matching the respective trial’s inclusion criteria. A targeted literature search for paid amounts directly associated with each CVD event provided the unit costs, which were applied to the projected number of events averted, to calculate costs avoided per member per year (PMPY). One-way sensitivity analyses were performed on events averted, unit costs, and percentages of trial-applicable patients.

Results: Based on three-point MACE events averted, costs avoided PMPY of $6.17 (range: $1.27–$10.94) for CANVAS and $2.75 ($0.19–$4.83) for EMPA-REG were estimated. Costs avoided for individual components of MACE ranged from $0.77 to $3.84 PMPY for CANVAS and from -$0.97 (additional costs) to $1.54 for EMPA-REG. PMPY costs avoided for heart failure were $2.72 for CANVAS and $1.32 for EMPA-REG.

Limitations and conclusions: Models assumed independent, non-recurrent outcomes and were restricted to medical costs directly associated with the trial-reported events. The reductions in CVD events in T2DM patients reported for both CANVAS and EMPA-REG project to a positive cost avoidance for these events in an MCO population. The analysis did not include an assessment of the impact on total cost, as the costs associated with adverse events, drug utilization or other clinical outcomes were not examined.     

Aid and public sector fiscal behaviour in failing states

This paper looks at interactions between foreign aid and the public sector in developing countries, especially those considered to be fragile or failing states. A model is proposed which employs actual budgetary appropriations and revenue estimates (rather than estimated target variables) and allows for asymmetric preferences. Variants of the model are estimated using time-series data for Papua New Guinea (PNG). PNG is classified as a fragile state by the international community owing to perceived policy and institutional inadequacies. Results obtained suggest that foreign aid increases consumption and investment expenditures and decreases tax revenues and the level of borrowing.     

电子商务B2C模式在乌鲁木齐旅行社的应用

发展电子商务是旅行社从传统经济时代过渡到网络经济时代的必需,也是参与市场竞争的取胜之道。乌鲁木齐旅行社在应用电子商务B2C模式的过程中还存在着一些不足。实践证明,加强宏观环境建设、增强信息意识、完善网络建设和加大人才培养是发展电子商务的有效途径。     

Capital Controls,Global Liquidity Traps,and the International Policy Trilemma*

The zero bound on interest rates introduces a new dimension to the trilemma in international policy. The openness of the international financial market might render monetary policy ineffective, even within a system of fully flexible exchange rates, because shocks that lead to a liquidity trap in one country are propagated through financial markets to other countries. However, the effectiveness of monetary policy can be restored by the imposition of capital controls. We derive the optimal response of monetary policy to a global liquidity trap in the presence of capital controls. We show that, even though capital controls might facilitate effective monetary policy, capital controls are not generally desirable in terms of welfare.     

Localized innovation, localized diffusion and the environment: an analysis of reductions of CO2 emissions by passenger cars

We investigate technological change with regard to CO₂ emissions by passenger cars, using a Free Disposal Hull methodology to estimate technological frontiers. We have a sample of cars available in the UK market in the period 2000–2007. Our results show that the rates of technological change (frontier movement) and diffusion (distance to frontier at the car brand level) differ substantially between segments of the car market. We conclude that successful policies should be aimed at the diffusion of best-practice technology, and take account of the different potential for further progress between different segments of the market (e.g. diesel vs. gasoline engines and small vs. large engines).