Utility Gain Research Articles

Heterogeneity in farmers’ production decisions and its impact on soil nutrient use: Results and implications from northern Nigeria

Sustainable use (in terms of nutrients) of soil resources by farmers in Sub-Saharan Africa is constrained by institutions and markets. This paper explores the case of northern Nigeria, by using a combination of multi-attribute utility theory and bio-economic modelling. This approach allowed us to identify heterogeneity in production strategies and to quantify its effect on the use of soil nutrient resources. We find that farmers with larger land holdings place more emphasis on gross margins in their utility function, while those with larger holdings of fertile fadama fields place more emphasis on sustainability. Risk aversion, operationalised through variance minimization, appears an important attribute in the utility function of many farm households that are more dependent on agriculture for their overall income. A regression analysis shows that differences in production strategies significantly affect nutrient balances, but also shows that such effects are heterogeneous across locations. We find more favourable nutrient balances for some of the more market-oriented farm households who place more emphasis on sustainability. In farm plans of the most risk-averse households, the production of cereals for subsistence consumption dominates and leads to negative soil nutrient balances, especially for potassium. Farmers who place a large importance on gross margins are likely to benefit most from policies aimed at enhancing profitability through improving functioning of markets. The large group of risk-averse farmers will have the largest immediate gain in utility from policies and technologies aimed at reducing production risk in high-value crops. Additional policies aimed at creating a stronger market-oriented production by the least-endowed farm households could play a role in reducing intensity of soil fertility mining. Under these conditions, the efficient cropping pattern shifts partially from cereal cropping to high-value crops, associated with higher input use. The main results are similar to those in other studies, although some of the nutrient balances are less negative. The results do appear to be sensitive to the type of cropping activities included in the analysis, and additional methodological research is required. Extensions of the used method should further account for temporal and spatial differences in soil fertility, leading to differences in nutrient uptake and production, as well as potential temporal heterogeneity in production strategies.

Obtaining the best value for money in adaptive sequential estimation

In [Kujala, J. V., Richardson, U., & Lyytinen, H. (2010). A Bayesian-optimal principle for learner-friendly adaptation in learning games. Journal of Mathematical Psychology, 54(2), 247–255], we considered an extension of the conventional Bayesian adaptive estimation framework to situations where each observable variable is associated with a certain random cost of observation. We proposed an algorithm that chooses each placement by maximizing the expected gain in utility divided by the expected cost. In this paper, we formally justify this placement rule as an asymptotically optimal solution to the problem of maximizing the expected utility of an experiment that terminates when the total cost overruns a given budget. For example, the cost could be defined as the random time taken by each trial in an experiment, and one might wish to maximize the expected total information gain over as many trials as can be completed in 15 min. A simple, analytically tractable example is considered.

The role of fairness norms the household-based natural forest conservation: The case of Wolong, China

The shadow of “the tragedy of the commons” with its popularized assumption of selfish individual behavior concerns policy-makers, and consequently the cooperative capability of local communities in common resource management is usually underrated. Nevertheless, here we propose a hypothesis, based on a game theory model, that the social norm of fairness rather than self-interest might motivate cooperation in natural resource conservation by discounting the utility gain from illegal logging at the cost of another household's subsidy loss. In Wolong Nature Reserve of China, a recent household-based natural forest conservation program has led to remarkable progress in protecting the habitat of giant pandas (Ailuropoda melanoleuca) with low monitoring pressure. We undertook experiments based on a one-shot Ultimatum Game to test the prevalence of the norm of fairness in the local communities. Most proposers in the experiments showed strong preferences for fair offers in spite of the responders' reluctance to reject low offers, and the result contradicted the expectation of pure self-interest. Taking into account the norm of fairness, the prediction of the model is consistent with the local performance of the household-based conservation policy. It highlights the potential of local social norms to facilitate participation and cooperation by the local community in common natural resource conservation.

Understanding the Relationship between the EQ-5D, SF-6D, HAQ and Disease Activity in Inflammatory Arthritis

The growth of economic analyses and in particular cost-utility analyses (CUA), which use the QALY as a measure of outcome, has heightened the interest in the methodologies used to calculate the QALY. The EQ-5D has produced quite different utility values from that of the SF-6D. This article seeks to understand these differences using a cohort of patients with inflammatory arthritis. To examine the relationship between the disease-specific measure, Health Assessment Questionnaire (HAQ) disability index (DI) and the preference-based measures, SF-6D, EQ-5D and European League Against Arthritis (EULAR) Disease Activity Score (DAS) in patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Patients with RA and PsA (n = 504) attending a tertiary rheumatology referral centre completed the HAQ, SF-6D and the EQ-5D before starting biological therapy and again 12 months later. The SF-36 was converted into a utility using the preference-based SF-6D. Clinical outcomes such as the DAS, joint counts and laboratory measures were also recorded. We calculated single index utility scores from the preference-based instruments using UK population norms. We used regression analysis to derive a mapping function and calculated utility scores from the HAQDI and the DAS 28. The mean utility observed at baseline for RA was 0.43 for the EQ-5D and 0.54 for the SF-6D and for PsA was 0.49 for the EQ-5D and 0.57 for the SF-6D. The utility gain demonstrated by the EQ-5D was over twice that of the SF-6D. The EQ-5D scored 17% of the RA group as less than 0 (state defined as worse than death); 7% of this group remained less than 0 at follow-up. The distribution of the utility estimates was similar for both RA and PsA. Our findings draw attention to the impact of states worse than death on the overall distribution for the EQ-5D derived utilities and how these impact on its use in practice. EQ-5D-derived QALY changes are over twice that of the SF-6D. The implication of this for decision makers is that cost-effectiveness evaluations for treatments in this disease class are likely to be very sensitive to the choice of utility measure.

Multiagent -Learning for Aloha-Like Spectrum Access in Cognitive Radio Systems

An Aloha-like spectrum access scheme without negotiation is considered for multiuser and multichannel cognitive radio systems. To avoid collisions incurred by the lack of coordination, each secondary user learns how to select channels according to its experience. Multiagent reinforcement leaning (MARL) is applied for the secondary users to learn good strategies of channel selection. Specifically, the framework of -learning is extended from single user case to multiagent case by considering other secondary users as a part of the environment. The dynamics of the -learning are illustrated using a Metrick-Polak plot, which shows the traces of -values in the two-user case. For both complete and partial observation cases, rigorous proofs of the convergence of multiagent -learning without communications, under certain conditions, are provided using the Robins-Monro algorithm and contraction mapping, respectively. The learning performance (speed and gain in utility) is evaluated by numerical simulations.

Utility‐based outcomes made easy: The number needed per quality‐adjusted life year gained. An observational cohort study of tumor necrosis factor blockade in inflammatory arthritis from Southern Sweden

To introduce a novel, simple, utility-based outcome measure, the number needed per quality-adjusted life year (QALY) gained (NNQ), and to apply it in clinical practice in anti-tumor necrosis factor (anti-TNF)-treated patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and spondylarthritis (SpA). The NNQ is the number of patients one has to treat in order to gain 1 QALY. It is calculated as the inverted value of the utility gain (area under the curve) over 1 year in a cohort subjected to an intervention. EuroQol Index utility data from the South Swedish Arthritis Treatment register were used. Patients with RA (n = 1,001), PsA (n = 241), and SpA (n = 255) were eligible for the study. First, second, and third treatment courses were studied. For RA, NNQ was 4.5, 6.4, and 5.2 for first, second, and third courses, respectively. For PsA and SpA, NNQ was 4.2-4.5, irrespective of treatment order. Treatment groups with <50 patients were not analyzed. During the study period 2002-2007, there were no secular trends of utility gains. The NNQ is an easily derived and understandable utility-based outcome measure that may be useful for stakeholders and decision makers as well as for clinicians. It was readily applied in this study of TNF blockade across 3 arthritis diagnoses. NNQ varied little over diagnoses and treatment course order, with a possible exception in second treatment course in RA.

Realistic data transfer scheduling with uncertainty

Next Generation Networks (NGNs) will be comprised of different access technologies. We are already seeing the emergence of mobile devices with the capability of connecting to heterogeneous networks with different capabilities and constraints. In addition, many bandwidth intensive applications have rather relaxed real-time constraints allowing for alternative scheduling mechanisms which can take into account user preferences, network characteristics as well as future network resource availability to better exploit network heterogeneity. The current approaches either simply react to changes, or assume that availability predictions are perfect. In this paper, we propose a scheduling scheme based on stochastic modeling to account for prediction errors. The scheme optimizes overall user utility gain considering imperfect predictions taken over realistic time intervals while catering for different applications’ needs. We use 180 days of real user data of many users to demonstrate that it consistently outperforms other non-stochastic and greedy approaches in typical networking environments.

Shedding new light on intrinsic motivation to work: evidence from a discrete choice experiment

In this paper, we evaluated the determinants of the decision utility of workers from the for-profit and nonprofit sectors. In our setting, decision utility is the weight assigned by workers to the expected benefits of different job offers. We used a conjoint analysis method based on experimental data on workers' stated preferences towards hypothetical job offers that were characterised by ten attributes. The intrinsic motivation of nonprofit workers was investigated by specifically analysing the influence of three of these attributes, specifically wages, working time, and loyalty of the employer, on decision utility. The results showed evidence of motivational differences between the for-profit and nonprofit groups. First, nonprofit workers attained their maximum decision utility after a longer working time, showing superior intrinsic motivation for work. Furthermore, they were ready to give up a higher percentage of their wages in order to work for another extra hour than were for-profit workers, as long as the working week was less than 33 hours. Finally, our findings show that for-profit workers placed more value on job offers with a labour contract including an explicit clause stating that higher effort will be exchanged for the employer's loyalty. In contrast, nonprofit workers did not obtain higher utility from such a deal. We interpret this result as evidence for the intrinsic motivation of people employed in the nonprofit sector. As the nature of the implicit goals pursued in the nonprofit sector provides employees with high work morale, nonprofit workers do not obtain any gain in utility from an explicit clause regarding the employer's loyalty.

Relay assignment and cooperation maintenance in wireless networks: a game theoretical approach

In this study, the authors study the relays assignment problem in cooperative wireless networks with self-interested nodes. The authors propose a cooperation mechanism which includes the cooperative relationship formation stage and cooperation maintenance stage. The cooperative relationship among the nodes can be modelled as an exchange market game where nodes trade transmission power between each other to obtain diversity gain. The exchange games have a basic assumption that each node conforms to trade agreement so that each agent has the option to trade its good to obtain a better one. In such a game, strict core is considered as individual rational, Pareto optimal and relationship-stable solution. A cooperation cycle formation (CCF) algorithm is proposed to obtain the strict core solution. However, in networks, some deviated nodes may break the cooperation agreement to obtain more utility gain. Such deviated behaviours in the cooperation cycles can totally destroy the cooperation relationship. However, the data transmissions in networks have the repeated element. Hence, based on the cooperative cycle formed by CCF, the authors introduce a repeated game model for cooperation maintenance in the second stage. A dynamic punishment and recover mechanism is proposed to punish the deviated behaviours and recover cooperation.

New Three-Level Resource Management Enhancing Quality of Offline Hardware Task Placement on FPGA

Currently, reconfigurable hardware devices feature a high density of heterogeneous resources to enable multitasking and offer flexibility in application needs. These concepts raise the need for efficient management of hardware tasks and hardware resources. The scheduling of hardware tasks is highly dependent on placement. Placement focuses on allocation of hardware resources required by the scheduled hardware tasks. In this paper, we propose novel three-level resource management that investigates enhancement of placement quality by reducing task rejection, configuration overheads, and by optimizing resource utilization. Improving placement quality will produce significant enhancement of performance for scheduling and overall execution time of the application in FPGA. Hence, the placement problem is formulated into a constrained optimization problem and resolved with powerful solvers using the Branch and Bound method. The obtained results of an application of heterogeneous hardware tasks show an average resource utilization of 36% of the available resources on the reconfigurable region and an overall overhead of 11% of total application running time, and we have eliminated the issue of task rejection. Compared to static implementation, the gain in resource utilization within the reconfigurable region achieves up to 43%.

The Impact of Corporate Social Performance on Financial Risk and Utility: A Longitudinal Analysis

This study focuses on the wealth-protective effects of socially responsible firm behavior by examining the association between corporate social performance (CSP) and financial risk for an extensive panel data sample of S&P 500 companies between the years 1992 and 2009. In addition, the link between CSP and investor utility is investigated. The main findings are that corporate social responsibility is negatively but weakly related to systematic firm risk and that corporate social irresponsibility is positively and strongly related to financial risk. The fact that both conventional and downside risk measures lead to the same conclusions adds convergent validity to the analysis. However, the risk-return trade-off appears to be such that no clear utility gain or loss can be realized by investing in firms characterized by different levels of social and environmental performance. Overall volatility conditions of the financial markets are shown to play a moderating role in the nature and strength of the CSP-risk relationship.

The effectiveness and cost-effectiveness of cochlear implants for severe to profound deafness in children and adults: a systematic review and economic model

To investigate whether it is clinically effective and cost-effective to provide (i) a unilateral cochlear implant for severely to profoundly deaf people (using or not using hearing aids), and (ii) a bilateral cochlear implant for severely to profoundly deaf people with a single cochlear implant (unilateral or unilateral plus hearing aid). Main electronic databases [MEDLINE; EMBASE; Cochrane Database of Systematic Reviews; CENTRAL; NHS EED; DARE; HTA (NHS-CRD); EconLit; National Research Register; and ClinicalTrials.gov] searched in October 2006, updated July 2007. A systematic review of the literature was undertaken according to standard methods. A state-transition (Markov) model of the main care pathways deaf people might follow and the main complications and device failures was developed. The clinical effectiveness review included 33 papers, of which only two were RCTs. They used 62 different outcome measures and overall were of moderate to poor quality. All studies in children comparing one cochlear implant with non-technological support or an acoustic hearing aid reported gains on all outcome measures, some demonstrating greater gain from earlier implantation. The strongest evidence for an advantage from bilateral over unilateral implantation was for understanding speech in noisy conditions (mean improvement 13.2%, p < 0.0001); those receiving their second implant earlier made greater gains. Comparison of bilateral with unilateral cochlear implants plus an acoustic hearing aid was compromised by small sample sizes and poor reporting, but benefits were seen with bilateral implants. Cochlear implants improved children's quality of life, and those who were implanted before attending school were more likely to do well academically and attend mainstream education than those implanted later. In adults, there was a greater benefit from cochlear implants than from non-technological support in terms of speech perception. Increased age at implantation may reduce effectiveness and there is a negative correlation between duration of deafness and effectiveness. Speech perception measures all showed benefits for cochlear implants over acoustic hearing aids [e.g. mean increase in score of 37 points in noisy conditions (p < 0.001) with BKB sentences]; however, prelingually deafened adults benefited less than those postlingually deafened (mean change scores 20% versus 62%). For unilateral versus bilateral implantation, benefits in speech perception were significant in noisy conditions on all measures [e.g. 76% for HINT sentences (p < 0.0001)]. Quality of life measured with generic and disease-specific instruments or by interview mostly showed significant gains or positive trends from using cochlear implants. The Markov model base-case analysis estimated that, for prelingually profoundly deaf children, the incremental cost-effectiveness ratio (ICER) for unilateral implantation compared with no implantation was 13,413 pounds per quality-adjusted life-year (QALY). Assuming the utility gain for bilateral implantation is the same for adults and children, the ICERs for simultaneous and sequential bilateral implantation versus unilateral implantation were 40,410 pounds and 54,098 pounds per QALY respectively. For postlingually sensorineurally profoundly deaf adults, the corresponding ICERs were 14,163 pounds, 49,559 pounds and 60,301 pounds per QALY respectively. Probabilistic threshold analyses suggest that unilateral implants are highly likely to be cost-effective for adults and children at willingness to pay thresholds of 20,000 pounds or 30,000 pounds per QALY. There are likely to be overall additional benefits from bilateral implantation, enabling children and adults to hold conversations more easily in social situations. Unilateral cochlear implantation is safe and effective for adults and children and likely to be cost-effective in profoundly deaf adults and profoundly and prelingually deaf children. However, decisions on the cost-effectiveness of bilateral cochlear implants should take into account the high degree of uncertainty within the model regarding the probable utility gain.

Discrete-time implementation of continuous-time portfolio strategies

Optimal portfolio strategies are easy to compute in continuous-time models. In reality trading is discrete, so that these optimal strategies cannot be implemented properly. When the investor follows a naive discretization strategy, i.e. when he implements the optimal continuous-time strategy in discrete time, he will suffer a utility loss. For a variety of models, we analyze this discretization error in a simulation study. We find that time discreteness can be neglected when only the stock and the money market account are traded, even in models with stochastic volatility and jumps. On the other hand, when derivatives are traded the utility loss due to discrete trading can be much larger than the utility gain from having access to derivatives. To benefit from derivatives, the investor has to rebalance his portfolio at least daily.

A Welfare Analysis of the Commonwealth Seniors Health Card*

The Commonwealth Seniors Health Card (CSHC) is a key element of a suite of benefits for Australia's ‘self‐funded retirees’. Its main component is a pharmaceutical concession, which is analysed as a form of public health insurance. The utility gain through risk‐pooling is found to be negligible under conservative assumptions. The deadweight loss through moral hazard may be considerable. Finally, the CSHC may be seen as an inequitable transfer, because CSHC holders are a particularly wealthy population.

Rapid and sustained health utility gain in anti-tumour necrosis factor-treated inflammatory arthritis: observational data during 7 years in southern Sweden

Background:Rheumatoid arthritis (RA), psoriatic arthritis (PsA) and other spondylarthritides impose a great impact on the individual in addition to the costs on society, which may be reduced by effective pharmacological...

Cost-Effectiveness of Testing for Breast Cancer Susceptibility Genes

Objectives Genetic mutations in breast cancer susceptibility genes BRCA1/2 are associated with an increased risk of breast/ovarian cancers. Cost-effective preventive measures are available for women who test positive. The objective of this study was to determine at what risk of mutation it is cost-effective to test women for BRCA1/2 mutations. Methods A semi-Markov model accrued costs and quality-adjusted life years (QALYs) annually from the societal perspective. The estimates of health-care costs, life expectancy, likelihood of obtaining a mastectomy or oophorectomy, and patient preferences for treatment and certainty about their BRCA1/2 status were based on the literature. Results At a 10% probability of mutation (the current guideline), the test strategy generated 22.9 QALYs over the lifetime and cost $118k, while the no-test strategy generated 22.7 QALYs and cost $117k. The incremental cost-effectiveness ratio of the test strategy was $9k and the differences between costs and effects were not substantial. The test strategy remained cost-effective to a probability of mutation of 0%, as long as utility gained from a negative test result was 0.006 or greater. These results were sensitive to the frequency of inconclusive test results and utility gain from a negative test result. Conclusions The costs and effectiveness of both the test and no-test strategies are very similar even when there is a small probability of mutation. Current guidelines, which can be used by insurance companies to refuse coverage, could deny some women a cost-effective approach. Further research to decrease the frequency of inconclusive results could improve the cost-effectiveness of this test.

Trade Sanctions, Financial Transfers and BRIC's Participation in Global Climate Change Negotiations

Countries can reduce global emissions by reducing own consumption since they are linked to the total value of consumption world wide. Two effects are at issue: a utility loss from forgone consumption and a utility gain from lowered temperature change. It is thus unclear whether own country emissions reductions are in the self interest; typically they are not for small countries, but may be for larger countries. Here are investigate the incentives for individual large population low wage rapidly growing countries in the BRIC group (Brazil, Russia, India, China) and the groups of countries as a sub-global coalition. We also assess what level of other countries’ trade measures linked to non participation is needed to induce compliance as an all or nothing discrete choice. We capture induced changes in the global trade equilibrium in our analysis, as well as participation linked to financial transfers. Our results suggest that only very high tariffs over a hundred percent by all other countries, or even higher tariffs by the OECD alone, could induce participation by BRIC countries, especially when the country is a net exporter. Equally, large financial transfers would be needed.

Multiagent Paradigm for the Agent Selection and Negotiation in a B2C Process

Multi-agent paradigms have been developed for the negotiation and brokering in B2C e-commerce .Few of the models consider the mental states and social settings (trust and reputation) but rarely any model depicts their combination. In this work, we present three mathematical models. First cognitive computational model which is combined model of belief, desire, intention (BDI) model for agent’s mental attitudes and social settings; is used for the computation of trust and then index of negotiation which is based on trust and reputation and the second computation model is developed for the computation of business index that characterizes the parameters of some of the business processes, which match the buyer’s satisfaction level. The third computation model of utility is used for negotiation between seller and buyer to achieve maximum combined utility increment (CUI) which is the difference of marginal utility gain (MUG) of buyer and marginal utility cost (MUC) of seller.

Deceased Donor Kidney Transplantation in Elderly Patients: Is There a Difference in Outcomes?

Introduction There is a paucity of data on long-term outcomes of older kidney recipients. Our aim was to compare the early and long-term outcomes of deceased donor kidney transplantation in patients aged ≥60 years with outcomes in younger recipients. Materials and Methods From 1998 to 2005, we performed 271 deceased donor kidney transplants. There were 76 recepients (28.1%) >60 years old. Older candidates were carefully selected based on their physiologic, cardiac, and performance status. Demographic data, including clinical characteristics, early complications, mortality, and patient and graft survival rates, were collected and analyzed. Results Older patients had comparable perioperative mortality and morbidity, incidence of delayed graft function (DGF), length of stay, and readmissions compared with younger patients. The rates of acute rejection and major infections were also comparable between the 2 study groups. Among older recipients, 25/76 (32.1%) patients received extended criteria donor kidneys compared with only 35/195 (17.9%) of younger patients ( P < .001). Nevertheless, equivalent 1-, 3-, and 5-year allograft survival rates were observed in elderly and young patients; 91.5% versus, 92.5%, 78.5% versus 81.9%, and 75.6% versus 78.5%, respectively. Overall patient survival was also comparable in both groups. Conclusion Kidney transplantation in appropriately selected elderly recipients provides equivalent outcomes compared with those observed in younger patients. These observations support the notion that older recipients should not lose access to deceased donor kidney transplantation in the effort to achieve a perceived gain in social utility.

Cost-effectiveness of pharmacological anti-obesity treatments: a systematic review

To review economic evaluations of weight loss drugs and compare reported incremental cost-effectiveness ratios (ICERs). A literature search was conducted for cost-effectiveness (CEAs) and cost-utility analyses (CUAs) of sibutramine, orlistat and rimonabant. Fourteen unique articles were identified (11 CUAs and 3 CEAs; 9 orlistat, 4 sibutramine and 1 rimonabant). All used diet and exercise as comparator, whereas none included indirect costs. Time horizons varied from treatment period only (1-4 years) to 80 years (median 7.5 years). Longer studies modeled effects on diabetes, micro- and macrovascular complications, coronary heart disease and death. Of the CUAs, the median ICER was 16,000 euro(2007)/QALY (quality-adjusted life-year; range 10,000-88,000), with the worst cost-effectiveness when recommended stop rules for non-responding patients were not applied. All studies but three were funded by the manufacturing company, and the median ICER was considerably higher for independent than for sponsored analyses (62,000 euro vs 15,000 euro/QALY). However, two of the three independent CUAs did not use recommended stop rules, as compared with one of eight manufacturer-sponsored analyses. The results were most sensitive to assumptions regarding weight loss sustainability and utility per kilogram lost. Side effects and dropout because of reasons other than lack of efficacy were generally not incorporated. Published economic evaluations indicate that orlistat, sibutramine and rimonabant are within the range of what is generally regarded as cost-effective. Uncertainty remains about weight loss sustainability, utility gain associated with weight loss and extrapolations from transient weight loss to long-term health benefits. Modeling of head-to-head comparisons and attrition is needed, as are analyses conducted independently of manufacturing companies.