Minimum cost spanning tree problems with indifferent agents

We consider an extension of minimum cost spanning tree (mcst) problems in which some agents do not need to be connected to the source, but might reduce the cost of others to do so. Even if the cost usually cannot be computed in polynomial time, we extend the characterization of the Kar solution (Kar, 2002) for classic mcst problems. It is obtained by adapting the Equal treatment property: if the cost of the edge between two agents changes, their cost shares are affected in the same manner if they have the same demand. If not, their changes are proportional to each other. We obtain a family of weighted Shapley values. Three interesting solutions in that family are characterized using stability, fairness and manipulation-proofness properties.     

A fair rule in minimum cost spanning tree problems

We study minimum cost spanning tree problems and define a cost sharing rule that satisfies many more properties than other rules in the literature. Furthermore, we provide an axiomatic characterization based on monotonicity properties.     

Cost monotonicity, consistency and minimum cost spanning tree games

We propose a new cost allocation rule for minimum cost spanning tree games. The new rule is a core selection and also satisfies cost monotonicity. We also give characterisation theorems for the new rule as well as the much-studied Bird allocation. We show that the principal difference between these two rules is in terms of their consistency properties.     

Pricing traffic in a spanning network

Users need to connect a pair of target nodes in the network. They share the fixed connection costs of the edge. The system manager elicits target pairs from users, builds the cheapest forest meeting all demands, and choose a cost sharing rule satisfying:Routing-proofness: a user cannot lower his cost by reporting as several users along an alternative path connecting his target nodes;Stand Alone core stability: no group of users pay more than the cost of a subnetwork meeting all connection needs of the group.We construct two such rules. When all connecting costs are 0 or 1, one is derived from the random spanning tree weighted by the volume of traffic on each edge; the other is the weighted Shapley value of the Stand Alone cooperative game. Both rules are then extended by the familiar piecewise-linear technique. The former is computable in polynomial time, the latter is not.     

A characterization of the Shapley value in queueing problems

A set of agents stand to receive a service. No two agents can be served simultaneously. A queue has to be organized, and agents having to wait should receive monetary compensations. We characterize the rule assigning positions in the queue and compensations corresponding to the payoffs recommended by the Shapley value of the associated cooperative game. We use a property of independence with respect to increase in some agents’ impatience, and an equal responsibility property.     

A characterization of a family of rules for the adjudication of conflicting claims

We consider the problem of adjudicating conflicting claims, and characterize the family of rules satisfying four standard invariance requirements, homogeneity, two composition properties, and consistency. It takes as point of departure the characterization of the family of two-claimant rules satisfying the first three requirements, and describes the restrictions imposed by consistency on this family and the further implications of this requirement for problems with three or more claimants. The proof, which is an alternative to Moulinʼs original proof [Moulin, H., 2000. Priority rules and other asymmetric rationing methods. Econometrica 68, 643–684], is based on a general method of constructing consistent extensions of two-claimant rules [Thomson, W., 2007. On the existence of consistent rules to adjudicate conflicting claims: a constructive geometric approach. Rev. Econ. Design 11, 225–251], which exploits geometric properties of paths of awards, seen in their entirety.     

A cost utility model of interferon beta-1b in the treatment of relapsing-remitting multiple sclerosis

SUMMARY

This study estimates the long-term cost effectiveness of Betaferon®, (interferon beta-1b) in the treatment of relapsing-remitting multiple sclerosis (RRMS). Clinical trial data, natural disease history information, and costs and quality of life (EQ-5D) data, are linked using disease severity levels, via a model that accounts for the number, severity and duration of relapses, and the probability and speed of disease progression. Previous attempts at modeling the cost effectiveness of beta interferon have produced very estimates of costs per QALY gained (CQG). Increasing data availability enables the modification or replacement of many of the assumptions underlying these models. In particular, longer term modeling and the consideration of wider societal costs is appropriate in the context of this chronic disease. The evidence presented here provides much lower, and more precise, estimates of CQG. The base case 20-year model estimates a CQG of £8,100. These new estimates are in line with other recent estimates and demonstrate the cost effectiveness of beta interferon.     

A comparison of embedded and forward-looking local loop cost estimates for small rural telephone companies in Illinois

It is often represented as axiomatic in the telephone industry that telephone company costs are determined to a significant degree by demographic characteristics of the companies’ service areas. This article compares and contrasts forward-looking and embedded cost estimates for a group of rural local phone companies in Illinois and further examines the relationship between the estimates generated by the two respective cost methodologies and demographic characteristics of the companies’ service areas. This examination shows that relative intercompany forward-looking cost estimates are determined to a significant degree by demographic factors, but that relative intercompany embedded cost estimates are not. The opinions in this paper do not reflect the views of the Illinois Commerce Commission or its other staff members.     

Economic cost of deforestation in semi-deciduous forests — A case of two forest districts in Ghana

The ecological, economic and socio-cultural roles of forests are under threat in Ghana due to the high rate of deforestation. Efforts are being made to combat this problem through rehabilitation measures. However, the costs of deforestation and restoration benefits are not adequately estimated. This paper fills in the gap in knowledge by providing an empirical estimation of the cost of deforestation in monetary terms. Primary data collected regarding timber, non-timber forest products and soils in semi-deciduous forests were analyzed using opportunity cost and replacement cost techniques. The results emphasize differences in the value of these forest goods and services lost annually. The largest losses were in stumpage fees, edible fruits, and avoided carbon emissions values. The results show that US$133,650,000 gross revenue, equivalent to 2.6% of the 2008 agricultural sector Gross Domestic Product, is lost annually. It can be concluded that restoring the degraded forest lands would bring benefits particularly to the local communities through increased stumpage revenues and harvest of non-timber forest products, as well as additional funds from carbon credits. It is recommended that stakeholders of forest resources are made aware of these costs in order to raise awareness of what they are losing through deforestation.     

A cost analysis of the management of attention-deficit/hyperactivity disorder (ADHD) in children in the UK

SUMMARY

A decision analysis was performed to model the effects and health economic differences of current UK management approaches to attention-deficit/hyperactivity disorder (ADHD) in children aged between 6 and 16 years. The approaches modelled were: medication using a standard immediate-release methylphenidate (MPH-IR) (once, twice or three times daily); medication using CONCERTA®XL (OROS®* methylphenidate; MPH), a long-acting once-daily formulation of methylphenidate; or behavioural therapy (BEH). Starting treatment with BEH alone resulted in the highest annual cost (UK£2,147), while the costs of starting treatment with MPH-IR alone (£1,332), or OROS®* MPH alone (£1,362) were comparable. Treatment switches to behavioural treatment or combined treatment (medication and behavioural) due to treatment failure occurred in 11.8% of OROS®* MPH and 24.2% of MPH-IR patients. Probabilistic sensitivity analyses showed that the results were sensitive towards treatment success and the proportion of patients with comorbidities, although conclusions were not altered. UK treatment costs over 1 year appear comparable regardless of whether patients were treated first with OROS®* MPH or MPH-IR. Treating patients first with BEH and then adding stimulant medication if needed resulted in higher overall annual treatment costs.

CONCERTA® XL and OROS® are trademarks of ALZA Corporation, USA.     

A UK analysis of the cost of switching renal transplant patients from an immediate-release to a prolonged-release formulation of tacrolimus based on differences in trough concentration variability

Background and aims:

Randomized controlled trials have shown that a once-daily prolonged-release (PR) tacrolimus formulation (PR tacrolimus; Advagraf), is non-inferior to a twice-daily immediate-release (IR) tacrolimus formulation (IR tacrolimus; Prograf) in terms of biopsy-proven acute rejection, graft failure and mortality in renal transplant recipients. However, relative to IR tacrolimus, PR tacrolimus exhibits reduced tacrolimus trough concentration variability, which has been associated with reduced graft failure. Based on these data, the present study evaluated the cost of switching UK renal transplant patients from IR tacrolimus to PR tacrolimus.

Methods:

UK-specific data on acute rejection, graft failure, and mortality were used to construct a budget impact model to assess the costs of switching from IR tacrolimus to PR tacrolimus on a 1:1?mg:mg basis. The model assumed that 3.1% of patients on PR tacrolimus had high tacrolimus trough concentration variability compared with 17.4% on IR tacrolimus, based on a study comparing PR tacrolimus and IR tacrolimus pharmacokinetics. A relative graft failure risk of 2.38 was applied to high variability patients based on data from a tacrolimus variability study in which 10/148 patients with low variability experienced graft failure, compared with 24/149 in the high variability group. Cost data were taken from the British National Formulary and 2012–2013 NHS tariff information.

Results:

The mean per-patient cost (including tacrolimus, concomitant immunosuppressive medications, dialysis after graft failure, and treatment for acute rejection) was GBP 26,941 (standard deviation [SD]?=?GBP 2765) with PR tacrolimus vs GBP 30,356 (SD?=?GBP 3085) for IR tacrolimus over a 5-year period, corresponding to a saving of GBP 3415 (SD?=?GBP 516) per patient or GBP 341,500 in a hypothetical 100-patient transplant center. Cost savings were driven primarily by lower dialysis costs resulting from the lower proportion of PR tacrolimus patients with high tacrolimus trough concentration variability (leading to lower graft failure risk).

Limitations:

The main limitation of the study was the use of heterogeneous data sources to capture the effect of within-patient variability on graft failure. The most important difference between the studies was the definition of the threshold between low and high within-patient variability. This was explored in sensitivity analyses in which the inter-arm difference in the inter-arm proportions of patients with high and low variability was abolished.

Conclusions:

Converting UK renal transplant recipients from IR tacrolimus to PR tacrolimus was associated with lower pharmacy and dialysis costs.     

A cost analysis of SIR-Spheres yttrium-90 resin microspheres versus tyrosine kinase inhibitors in the treatment of unresectable hepatocellular carcinoma in France,Italy, Spain and the UK

Abstract

Background and aims: A wide range of treatment options are available for hepatocellular carcinoma (HCC), including systemic treatment with tyrosine kinase inhibitors (TKIs) such as sorafenib and lenvatinib, immunotherapies, locoregional therapies such as selective internal radiation therapy (SIRT) and treatments with curative intent such as resection, radiofrequency ablation and liver transplantation. Given the substantial economic burden associated with HCC treatment, the aim of the present analysis was to establish the cost of using SIRT with SIR-Spheres yttrium-90 (Y-90) resin microspheres versus TKIs from healthcare payer perspectives in France, Italy, Spain and the United Kingdom (UK).

Methods: A cost model was developed to capture the costs of initial systemic treatment with sorafenib (95%) or lenvatinib (5%) versus SIRT in patients with HCC in Barcelona Clinic Liver Cancer (BCLC) stages B and C. A nested Markov model was utilized to model transitions between progression-free survival (PFS), progression and death, in addition to transitions between subsequent treatment lines. Cost and resource use data were identified from published sources in each of the four countries.

Results: Relative to TKIs, SIRT with SIR-Spheres Y-90 resin microspheres were found to be cost saving in all four country settings, with the additional costs of the microspheres and the SIRT procedure being more than offset by reductions in drug and drug administration costs, and treatment of adverse events. Across the four country settings, total cost savings with SIR-Spheres Y-90 resin microspheres fell within the range 5.4–24.9% and SIRT resulted in more patients ultimately receiving treatments with curative intent (4.6 vs. 1.4% of eligible patients).

Conclusion: SIR-Spheres Y-90 resin microspheres resulted in cost savings relative to TKIs in the treatment of unresectable HCC in all four country settings, while increasing the proportion of patients who become eligible for treatments with curative intent.