Experimental measurement of preferences in health care using best-worst scaling (BWS): theoretical and statistical issues.

For optimal solutions in health care, decision makers inevitably must evaluate trade-offs, which call for multi-attribute valuation methods. Researchers have proposed using best-worst scaling (BWS) methods which seek to extract information from respondents by asking them to identify the best and worst items in each choice set. While a companion paper describes the different types of BWS, application and their advantages and downsides, this contribution expounds their relationships with microeconomic theory, which also have implications for statistical inference. This article devotes to the microeconomic foundations of preference measurement, also addressing issues such as scale invariance and scale heterogeneity. Furthermore the paper discusses the basics of preference measurement using rating, ranking and stated choice data in the light of the findings of the preceding section. Moreover the paper gives an introduction to the use of stated choice data and juxtaposes BWS with the microeconomic foundations.

Tactical Vehicle Routing Planning with Application to Milk Collection and Distribution

De nombreux problèmes pratiques qui se posent dans dans le domaine de la logistique, peuvent être modélisés comme des problèmes de tournées de véhicules. De façon générale, cette famille de problèmes implique la conception de routes, débutant et se terminant à un dépôt, qui sont utilisées pour distribuer des biens à un nombre de clients géographiquement dispersé dans un contexte où les coûts associés aux routes sont minimisés. Selon le type de problème, un ou plusieurs dépôts peuvent-être présents. Les problèmes de tournées de véhicules sont parmi les problèmes combinatoires les plus difficiles à résoudre. Dans cette thèse, nous étudions un problème d’optimisation combinatoire, appartenant aux classes des problèmes de tournées de véhicules, qui est liée au contexte des réseaux de transport. Nous introduisons un nouveau problème qui est principalement inspiré des activités de collecte de lait des fermes de production, et de la redistribution du produit collecté aux usines de transformation, pour la province de Québec. Deux variantes de ce problème sont considérées. La première, vise la conception d’un plan tactique de routage pour le problème de la collecte-redistribution de lait sur un horizon donné, en supposant que le niveau de la production au cours de l’horizon est fixé. La deuxième variante, vise à fournir un plan plus précis en tenant compte de la variation potentielle de niveau de production pouvant survenir au cours de l’horizon considéré. Dans la première partie de cette thèse, nous décrivons un algorithme exact pour la première variante du problème qui se caractérise par la présence de fenêtres de temps, plusieurs dépôts, et une flotte hétérogène de véhicules, et dont l’objectif est de minimiser le coût de routage. À cette fin, le problème est modélisé comme un problème multi-attributs de tournées de véhicules. L’algorithme exact est basé sur la génération de colonnes impliquant un algorithme de plus court chemin élémentaire avec contraintes de ressources. Dans la deuxième partie, nous concevons un algorithme exact pour résoudre la deuxième variante du problème. À cette fin, le problème est modélisé comme un problème de tournées de véhicules multi-périodes prenant en compte explicitement les variations potentielles du niveau de production sur un horizon donné. De nouvelles stratégies sont proposées pour résoudre le problème de plus court chemin élémentaire avec contraintes de ressources, impliquant dans ce cas une structure particulière étant donné la caractéristique multi-périodes du problème général. Pour résoudre des instances de taille réaliste dans des temps de calcul raisonnables, une approche de résolution de nature heuristique est requise. La troisième partie propose un algorithme de recherche adaptative à grands voisinages où de nombreuses nouvelles stratégies d’exploration et d’exploitation sont proposées pour améliorer la performances de l’algorithme proposé en termes de la qualité de la solution obtenue et du temps de calcul nécessaire.

Scoring rules and abnormally low bids criteria in construction tenders: a taxonomic review

In the global construction context, the best value or most economically advantageous tender is becoming a widespread approach for contractor selection, as an alternative to other traditional awarding criteria such as the lowest price. In these multi-attribute tenders, the owner or auctioneer solicits proposals containing both a price bid and additional technical features. Once the proposals are received, each bidder’s price bid is given an economic score according to a scoring rule, generally called an economic scoring formula (ESF) and a technical score according to pre-specified criteria. Eventually, the contract is awarded to the bidder with the highest weighted overall score (economic + technical). However, economic scoring formula selection by auctioneers is invariably and paradoxically a highly intuitive process in practice, involving few theoretical or empirical considerations, despite having been considered traditionally and mistakenly as objective, due to its mathematical nature. This paper provides a taxonomic classification of a wide variety of ESFs and abnormally low bids criteria (ALBC) gathered in several countries with different tendering approaches. Practical implications concern the optimal design of price scoring rules in construction contract tenders, as well as future analyses of the effects of the ESF and ALBC on competitive bidding behaviour.

Scoring rules and competitive behavior in best value construction auctions

This paper examines the extent to which engineers can influence the competitive behavior of bidders in Best Value or multi-attribute construction auctions, where both the (dollar) bid and technical non-price criteria are scored according to a scoring rule. From a sample of Spanish construction auctions with a variety of bid scoring rules, it is found that bidders are influenced by the auction rules in significant and predictable ways. The bid score weighting, bid scoring formula and abnormally low bid criterion are variables likely to influence the competitiveness of bidders in terms of both their aggressive/conservative bidding and concentration/dispersion of bids. Revealing the influence of the bid scoring rules and their magnitude on bidders’ competitive behavior opens the door for the engineer to condition bidder competitive behavior in such a way as to provide the balance needed to achieve the owner’s desired strategic outcomes.

On the communal analysis suspicion scoring for identity crime in streaming credit applications

This paper describes a rapid technique: communal analysis suspicion scoring (CASS), for generating numeric suspicion scores on streaming credit applications based on implicit links to each other, over both time and space. CASS includes pair-wise communal scoring of identifier attributes for applications, definition of categories of suspiciousness for application-pairs, the incorporation of temporal and spatial weights, and smoothed k-wise scoring of multiple linked application-pairs. Results on mining several hundred thousand real credit applications demonstrate that CASS reduces false alarm rates while maintaining reasonable hit rates. CASS is scalable for this large data sample, and can rapidly detect early symptoms of identity crime. In addition, new insights have been observed from the relationships between applications.

Risk-based trust management for e-commerce

Electronic commerce (e-commerce) offers enormous opportunities for online trading while at the same time presenting potential risks. Although various mechanisms have been developed to elevate trust in e-commerce, research shows that shoppers continue to be skeptical about buying online and lack of trust is often cited as the main reason for it. Thus, enhancing success in e-commerce requires eliminating or reducing the risks. In this chapter, we present a multi-attribute trust management model that incorporates trust, transaction costs and product warranties. The new trust management system enables potential buyers to determine the risk level of a product before committing to proceed with the transaction. This is useful to online buyers as it allows them to be aware of the risk level and subsequently take the appropriate actions to minimize potential risks before engaging in risky businesses. Results of various simulation experiments show that the proposed multi-attribute trust management system can be highly effective in identifying risky transaction in electronic market places.

Implementation of a quality care management system for patients with arthritis of the hip and knee

The Orthopaedic Unit of the Repatriation General Hospital (RGH) in Adelaide, South Australia has implemented a quality care management system for patients with arthritis of the hip and knee. The system not only optimises conservative management but ensures that joint replacement surgery is undertaken in an appropriate and timely manner. This new service model addresses identified barriers to service access and provides a comprehensive, coordinated strategy for patient management. Over 4 years the model has reduced waiting times for initial outpatient assessment from 8 to 3 months and surgery from 18 to 8 months, while decreasing length of stay from 6.3 to 5.3 days for hips and 5.8 to 5.3 days for knees. The service reforms have been accompanied by positive feedback from patients and referring general practitioners in relation to the improved coordination of care and enhanced efficiency in service delivery.

What is known about the topic? Several important initiatives both overseas and within Australia have contributed significantly to the development of this model of care. These include the UK National Health Service ‘18 weeks’ Project, the Western Canada Waiting List Project, the New Zealand priority criteria project, the Queensland Health Orthopaedic Physiotherapy Screening Clinic, and most importantly the Melbourne Health–University of Melbourne Orthopaedic Waiting List Project where a wide range of models were explored across Victorian hospitals from 2005 and the Multi-Attribute Prioritisation Tool (MAPT) was developed, validated and tested. This project became the Osteoarthritis Hip and Knee Service (OAHKS) and was operationalised in the Victorian healthcare system from 2012. These initiatives examined and addressed various aspects of management systems for patients with arthritis of the hip and knee in their particular setting.

What does this paper add? The development of this system is an extension of what is already known and is the first to encompass a comprehensive and coordinated strategy across all stages of the care management pathway for this patient group. Their management extends from the initial referral to development and implementation of a management plan, including surgery if assessed as necessary and organisation of long-term post operative follow up as required. By detailing the elements, key processes and measurable outcomes of the service redesign this paper provides a model for other institutions to implement a similar initiative.

What are the implications for practitioners? An important aspect of the design process was practitioner acceptance and engagement and the ability to improve their capacity to deliver services within an efficient and effective model. Intrinsic to the model’s development was assessment of practitioner satisfaction. Data obtained including practitioner surveys indicated an increased level of both satisfaction with the redesigned management service, and confidence in it to deliver its intended improvements.

Um modelo de leilões com conteúdo local: análise e modelagem dos leilões de concessão de blocos exploratórios de petróleo e gás promovidos pela ANP no Brasil

Os leilões para concessão de blocos de petróleo no Brasil utilizam uma equação para formar a pontuação que define o vencedor. Cada participante deve submeter ao leiloeiro um lance composto por três atributos: Bônus de Assinatura (BA), Programa Exploratório Mínimo (PEM) e Conteúdo Local (CL). Cada atributo possui um peso na equação e a nota final de cada participante também depende dos lances ofertados pelos outros participantes. Apesar de leilões de petróleo serem muito estudados na economia, o leilão multi-atributos, do tipo máxima pontuação, ainda é pouco analisado, principalmente como mecanismo de alocação de direitos minerários. Este trabalho destaca a inserção do CL como atributo que transforma a estrutura, do que poderia ser um leilão simples de primeiro preço, em um leilão multi-atributos de máxima pontuação. Demonstra-se como o CL, através da curva de custos do projeto, está relacionado também ao Bônus de Assinatura, outro importante atributo da equação. Para compreender o impacto do fenômeno da inserção do CL, foram criados três casos de leilões hipotéticos, onde, dentre outras simplificações, o programa exploratório mínimo foi fixado para todas as empresas envolvidas. No caso base (Sem CL), simula-se a estrutura de um leilão de primeiro preço, onde apenas o BA define o vencedor do leilão. Já no caso forçado (CLO=CLR), há inserção do atributo CL, sendo o participante obrigado a cumprir o CL ofertado. Por fim, o caso completo (Com Multa) permite que o participante preveja a aplicação de multa por descumprimento do CL ofertado e, caso haja benefício econômico, descumpra efetivamente o CL ofertado. Considerando estes casos, argumenta-se que, apesar do o lucro das empresas e a eficiência do leilão não serem alterados, a inclusão do conteúdo local na estrutura do leilão pode ter reflexos consideráveis na receita do governo.

In defence of modeling simultaneity for a correct approximation of cultural aspects: implications for food consumers studies with latent variables

Dealing with latent constructs (loaded by reflective and congeneric measures) cross-culturally compared means studying how these unobserved variables vary, and/or covary each other, after controlling for possibly disturbing cultural forces. This yields to the so-called ‘measurement invariance’ matter that refers to the extent to which data collected by the same multi-item measurement instrument (i.e., self-reported questionnaire of items underlying common latent constructs) are comparable across different cultural environments. As a matter of fact, it would be unthinkable exploring latent variables heterogeneity (e.g., latent means; latent levels of deviations from the means (i.e., latent variances), latent levels of shared variation from the respective means (i.e., latent covariances), levels of magnitude of structural path coefficients with regard to causal relations among latent variables) across different populations without controlling for cultural bias in the underlying measures. Furthermore, it would be unrealistic to assess this latter correction without using a framework that is able to take into account all these potential cultural biases across populations simultaneously. Since the real world ‘acts’ in a simultaneous way as well. As a consequence, I, as researcher, may want to control for cultural forces hypothesizing they are all acting at the same time throughout groups of comparison and therefore examining if they are inflating or suppressing my new estimations with hierarchical nested constraints on the original estimated parameters. Multi Sample Structural Equation Modeling-based Confirmatory Factor Analysis (MS-SEM-based CFA) still represents a dominant and flexible statistical framework to work out this potential cultural bias in a simultaneous way. With this dissertation I wanted to make an attempt to introduce new viewpoints on measurement invariance handled under covariance-based SEM framework by means of a consumer behavior modeling application on functional food choices.

Physicochemical parameters of water sample the four coastal lagoons at the Peninsula of Yucatan

Study sites. Samples of surface water were taken from 4 coastal lagoons on the Yucatan Peninsula in Mexico: Celestun (20° 45' N - 90° 22' W), Chelem (21° 15' N - 89° 45' W), Rosada Lagoon (21º 19' N - 89º 19' W), and Sabancuy Estuary (18° 58' N - 91° 12' W). The sampling was performed from august to October of 2011 (Chelem 08/24; Laguna Rosada 09/06; Celestún 09/28; Sabancuy 10/25). The sampling was random without replacement and 10 samples of surface water were collected along a transect parallel to the coastal axis. Samples were deposited in sterile plastic bottles and conserved in refrigeration at 4°C. All samples were processed within 24 hours after sampling. According to the Mexican laws and regulations no permissions are required to obtain water and sediment samples from open public areas. Analysis of environmental and physicochemical parameters. Determinations of the environmental parameters were performed with a Hach 5465000 model 156 multi-parameter measuring instrument. The Lorenzen method was used to determine chlorophyll-a (21) with 90% acetone and the concentration was calculated according to the formula: Chla= 27.63 (OD665o - OD665a)(VA)/VM x L Where, OD665o: absorbance at 665 nm before acidification; OD665a: absorbance at 665 nm after acidification; VA: volume (ml) of acetone for extraction; VM: volume (ml) of filtered water; L: length (cm) of the photometric cell. Determinations of the physicochemical parameters (silicates, phosphates, nitrates, nitrites and ammonia) were performed using the spectrophotometric techniques described and modified by Strickland and Parsons (1972).

MOIRA-PLUS use in decision making on the long-term management of contaminated freshwater bodies and catchments

In the mid-long-term after a nuclear accident, the contamination of drinking water sources, fish and other aquatic foodstuffs, irrigation supplies and people?s exposure during recreational activities may create considerable public concern, even though dose assessment may in certain situations indicate lesser importance than for other sources, as clearly experienced in the aftermath of past accidents. In such circumstances there are a number of available countermeasure options, ranging from specific chemical treatment of lakes to bans on fish ingestion or on the use of water for crop irrigation. The potential actions can be broadly grouped into four main categories, chemical, biological, physical and social. In some cases a combination of actions may be the optimal strategy and a decision support system (DSS) like MOIRA-PLUS can be of great help to optimise a decision. A further option is of course not to take any remedial actions, although this may also have significant socio-economic repercussions which should be adequately evaluated. MOIRA-PLUS is designed to allow for a reliable assessment of the long-term evolution of the radiological situation and of feasible alternative rehabilitation strategies, including an objective evaluation of their social, economic and ecological impacts in a rational and comprehensive manner. MOIRA-PLUS also features a decision analysis methodology, making use of multi-attribute analysis, which can take into account the preferences and needs of different types of stakeholders. The main functions and elements of the system are described summarily. Also the conclusions from end-user?s experiences with the system are discussed, including exercises involving the organizations responsible for emergency management and the affected services, as well as different local and regional stakeholders. MOIRAPLUS has proven to be a mature system, user friendly and relatively easy to set up. It can help to better decisionmaking by enabling a realistic evaluation of the complete impacts of possible recovery strategies. Also, the interaction with stakeholders has allowed identifying improvements of the system that have been recently implemented.

Alternativas de análise para experimentos G × E multiatributo

Geralmente, nos experimentos genótipo por ambiente (G × E) é comum observar o comportamento dos genótipos em relação a distintos atributos nos ambientes considerados. A análise deste tipo de experimentos tem sido abordada amplamente para o caso de um único atributo. Nesta tese são apresentadas algumas alternativas de análise considerando genótipos, ambientes e atributos simultaneamente. A primeira, é baseada no método de mistura de máxima verossimilhança de agrupamento - Mixclus e a análise de componentes principais de 3 modos - 3MPCA, que permitem a análise de tabelas de tripla entrada, estes dois métodos têm sido muito usados na área da psicologia e da química, mas pouco na agricultura. A segunda, é uma metodologia que combina, o modelo de efeitos aditivos com interação multiplicativa - AMMI, modelo eficiente para a análise de experimentos (G × E) com um atributo e a análise de procrustes generalizada, que permite comparar configurações de pontos e proporcionar uma medida numérica de quanto elas diferem. Finalmente, é apresentada uma alternativa para realizar imputação de dados nos experimentos (G × E), pois, uma situação muito frequente nestes experimentos, é a presença de dados faltantes. Conclui-se que as metodologias propostas constituem ferramentas úteis para a análise de experimentos (G × E) multiatributo.

Coordenação da entrega de ajuda a vítimas de desastre: uma abordagem multicritério com pensamento focado em valor.

Este trabalho trata da logística envolvida em operações de resposta a desastres, com foco na entrega final de suprimentos destinados a ajudar vítimas. Seu propósito é investigar os objetivos pertinentes ao planejamento do transporte da carga e encontrar uma metodologia para definir estratégia que sirva à tomada de decisão em campo. Para tanto, primeiramente identifica-se os objetivos adotados em modelos de Pesquisa Operacional para a tarefa em questão, através da análise de conteúdo das publicações pertinentes. Então, a abordagem do Pensamento Focado em Valores é utilizada para estruturar o problema. Finalmente, o método Simple Multi-Attribute Rating Technique Exploiting Ranks (SMARTER) é empregado na construção de um modelo de Análise da Decisão Multicritério (ADM), com consulta a um profissional experiente da área humanitária e aproveitando a análise da literatura previamente realizada. Neste processo, são elaboradas e avaliadas seis alternativas para a tomada de decisão condizentes com os valores da comunidade humanitária. Os resultados obtidos mostram que existe incompatibilidade entre os critérios de desempenho identificados nas publicações existentes e os objetivos perseguidos pelo Tomador da Decisão (TD) real. De acordo com o modelo construído, o atendimento de prioridades e a manutenção da sustentabilidade da operação são os objetivos que devem ser levados em conta para planejar a entrega de carga em pós-desastre, sendo que o custo e a equidade da distribuição não devem ser considerados. Conclui-se que o método adotado é útil à definição destes critérios e também ao desenvolvimento de estratégias que resultem em distribuições de ajuda melhores, aos olhos do próprio TD. Desta forma, ressalta-se que este trabalho contribui à área da Logística Humanitária com a investigação dos objetivos, assim como ao campo da ADM pela formalização dos processos de elaboração de alternativas, além da adição de mais uma aplicação possível ao repertório do método SMARTER.

Levonorgestrel intrauterine system versus medical therapy for menorrhagia

Background - Menorrhagia is a common problem, yet evidence to inform decisions about therapy is limited. In a pragmatic, multicenter, randomized trial, we compared the levonorgestrel-releasing intrauterine system (levonorgestrel-IUS) with usual medical treatment in women with menorrhagia who presented to their primary care providers. Methods - We randomly assigned 571 women with menorrhagia to treatment with levonorgestrel-IUS or usual medical treatment (tranexamic acid, mefenamic acid, combined estrogen–progestogen, or progesterone alone). The primary outcome was the patient-reported score on the Menorrhagia Multi-Attribute Scale (MMAS) (ranging from 0 to 100, with lower scores indicating greater severity), assessed over a 2-year period. Secondary outcomes included general quality-of-life and sexual-activity scores and surgical intervention. Results - MMAS scores improved from baseline to 6 months in both the levonorgestrel-IUS group and the usual-treatment group (mean increase, 32.7 and 21.4 points, respectively; P<0.001 for both comparisons). The improvements were maintained over a 2-year period but were significantly greater in the levonorgestrel-IUS group than in the usual-treatment group (mean between-group difference, 13.4 points; 95% confidence interval, 9.9 to 16.9; P<0.001). Improvements in all MMAS domains (practical difficulties, social life, family life, work and daily routine, psychological well-being, and physical health) were significantly greater in the levonorgestrel-IUS group than in the usual-treatment group, and this was also true for seven of the eight quality-of-life domains. At 2 years, more of the women were still using the levonorgestrel-IUS than were undergoing the usual medical treatment (64% vs. 38%, P<0.001). There were no significant between-group differences in the rates of surgical intervention or sexual-activity scores. There were no significant differences in serious adverse events between groups. Conclusions - In women with menorrhagia who presented to primary care providers, the levonorgestrel-IUS was more effective than usual medical treatment in reducing the effect of heavy menstrual bleeding on quality of life. (Funded by the National Institute of Health Research Health Technology Assessment Programme; ECLIPSE Controlled-Trials.com number, ISRCTN86566246.)

Levonorgestrel intrauterine system versus medical therapy for menorrhagia

ABSTRACT: Menorrhagia is a common problem that interferes with a woman’s physical, emotional, and social life. Evidence to guide physicians for decision about therapy for heavy menstrual bleeding is lacking. One treatment option, the levonorgestrel-releasing intrauterine system (levonorgestrel-IUS), has been available in the United States since 2009. Updated meta-analyses comparing the levonorgestrel-IUS with nonhormonal and hormonal treatments showed that the levonorgestrel-IUS produced a greater reduction in menstrual blood loss at 3 to 12 months of follow-up. It is not clear whether these short-term benefits persist. Moreover, the rates of discontinuation of the levonorgestrel-IUS at 2 years are as high as 28%, and effects on bleeding-related quality of life are not known. This pragmatic, multicenter, randomized trial compared the effectiveness of the levonorgestrel-IUS with that of usual medical treatment among women with menorrhagia in a primary care setting. A total of 571 women with menorrhagia were randomized to treatment with levonorgestrel-IUS (n = 285) or usual medical treatment (n = 286). Usual treatment was tranexamic acid, mefenamic acid, combined estrogen-progestogen, or progesterone alone. The primary study outcome measure was the patient-reported score on the condition-specific Menorrhagia Multi-Attribute Scale (MMAS) assessed over a 2-year period. The MMAS scores range from 0 to 100, with lower scores indicating greater severity. Summary MMAS scores were assessed at 6, 12, and 24 months. Secondary outcome measures included general health-related quality of life, sexual-activity scores, and surgical intervention. There was a significant improvement in total MMAS scores from baseline to 6 months in both the levonorgestrel-IUS group and the usual-treatment group; the mean increase was 32.7 and 21.4 points, respectively; P < 0.001 for both comparisons. Over the 2-year follow-up, improvements were maintained in both groups but were significantly greater in the levonorgestrel-IUS group (mean between-group difference, 13.4 points; 95% confidence interval, 9.9–16.9; P < 0.001). Significantly greater improvements in all MMAS domains (practical difficulties, social life, psychological health, physical health, work and daily routine, and family life and relationships) occurred with the levonorgestrel-IUS than with the usual treatment (P < 0.001 with the use of a test for trend). This was also found for 7 of the 8 quality-of-life domains. At the 2-year end point, almost twice as many women were still using the levonorgestrel-IUS than were those receiving the usual medical treatment (64% vs 38%, P < 0.001). No significant between-group differences were noted in the rates of surgical intervention or sexual-activity scores as well as in the frequency of serious adverse events. These data show that levonorgestrel-IUS is more effective than usual medical treatment in improving the quality of life of women with menorrhagia in a primary care setting.