Decision making techniques with similarity measures and OWA operators

We analyse the use of the ordered weighted average (OWA) in decision-making giving special attention to business and economic decision-making problems. We present several aggregation techniques that are very useful for decision-making such as the Hamming distance, the adequacy coefficient and the index of maximum and minimum level. We suggest a new approach by using immediate weights, that is, by using the weighted average and the OWA operator in the same formulation. We further generalize them by using generalized and quasi-arithmetic means. We also analyse the applicability of the OWA operator in business and economics and we see that we can use it instead of the weighted average. We end the paper with an application in a business multi-person decision-making problem regarding production management

Speed-cohesion trade-offs in collective decision making in ants and the concept of precision in animal behaviour

In decision making, speed-accuracy trade-offs are well known and often inevitable because accuracy depends on being well informed and gathering information takes time. However, trade-offs between speed and cohesion, that is the degree to which a group remains together as a single entity, as a result of their decision making, have been comparatively neglected. We combine theory and experimentation to show that in decision-making systems, speed-cohesion trade-offs are a natural complement to speed-accuracy trade-offs and are therefore of general importance. We then analyse the decision performance of 32 rock ant, Temnothorax albipennis, colonies in experiments in which accuracy of collective decision making was held constant, but time urgency varied. These experiments reveal for the first time an adaptive speed-cohesion trade-off in collective decision making and how this is achieved. In accord with different time constraints, colonies can decide quickly, at the cost of social unity, or they can decide slowly with much greater cohesion. We discuss the similarity between cohesion and the term precision as used in statistics and engineering. This emphasizes the generality of speed versus cohesion/precision trade-offs in decision making and decision implementation in other fields within animal behaviour such as sexually selected motor displays and even certain aspects of birdsong. We also suggest that speed versus precision trade-offs may occur when individuals within a group need to synchronize their activity, and in collective navigation, cooperative hunting and in certain escape behaviours.

Weber's law in decision making: integrating behavioral data in humans with a neurophysiological model

Recent single-cell studies in monkeys (Romo et al., 2004) show that the activity of neurons in the ventral premotor cortex covaries with the animal's decisions in a perceptual comparison task regarding the frequency of vibrotactile events. The firing rate response of these neurons was dependent only on the frequency differences between the two applied vibrations, the sign of that difference being the determining factor for correct task performance. We present a biophysically realistic neurodynamical model that can account for the most relevant characteristics of this decision-making-related neural activity. One of the nontrivial predictions of this model is that Weber's law will underlie the perceptual discrimination behavior. We confirmed this prediction in behavioral tests of vibrotactile discrimination in humans and propose a computational explanation of perceptual discrimination that accounts naturally for the emergence of Weber's law. We conclude that the neurodynamical mechanisms and computational principles underlying the decision-making processes in this perceptual discrimination task are consistent with a fluctuation-driven scenario in a multistable regime.

Clinical and laboratory predictors of imported malaria in an outpatient setting: an aid to medical decision making in returning travellers with fever

Si le tableau clinique évoque une malaria et que le résultat des examens parasitologiques n?est pas disponible ou est négatif, le praticien n?a pas d?information basée sur l?évidence pour savoir s?il doit donner ou non un traitement présomptif. Afin d?identifier les facteurs cliniques et paracliniques prédictifs d?une parasitémie à Plasmodium, nous avons mené une étude prospective chez les voyageurs ou migrants en provenance d?une zone tropicale ou subtropicale et qui consultaient pour de la fièvre. Le questionnaire comprenait 49 items explorant les données démographiques, les caractéristiques du voyage, les éléments de l?anamnèse et de l?examen clinique ainsi que les résultats de laboratoire. 336 sujets avec données complètes ont été recrutés (97 patients atteints de malaria et 239 contrôles avec fièvre et examen parasitologique négatif). L?analyse de régression multivariée a permis d?identifier les facteurs prédictifs de maiaria suivants : prophylaxie inadéquate, sudations, absence de douleur abdominale, température )38"C, mauvais état général, splénomégalie, compte leucocytaire (1 O x 1 03/L, plaquettes ~ 1 5 0 x l 03/L, taux d?hémoglobine <12 g/dL et éosinophiles (5%. La présence d?une splénomégalie avait le coefficient de probabilité positif pour un diagnostic de malaria le plus élevé (1 3.6) ; venait ensuite la présence d?une thrombopénie (1 1 .O). Dans le contexte de la consultation ambulatoire de la Policlinique Médicale Universitaire (prévalence de malaria de 29%), la probabilité post- test d?avoir un examen parasitologique positif était de 85% pour la splénomégalie et de 82% pour la thrombopénie. Même si le seuil thérapeutique n?est pas absolument défini, il semble raisonnable d?envisager un traitement présomptif lorsque la probabilité post- test est >80%. Si le médecin est réticent à administrer un traitement sans documentation parasitologique, il devrait au moins se retenir d?entreprendre d?autres investigations coûteuses, et plutôt répéter l?examen parasitologique après 12-24 heures.

Collective decision making in a heterogeneous environment: Lasius niger colonies preferentially forage at easy to learn locations

Many ants forage in complex environments and use a combination of trail pheromone information and route memory to navigate between food sources and the nest. Previous research has shown that foraging routes differ in how easily they are learned. In particular, it is easier to learn feeding locations that are reached by repeating (e.g. left-left or right-right) than alternating choices (left-right or right-left) along a route with two T-bifurcations. This raises the hypothesis that the learnability of the feeding sites may influence overall colony foraging patterns. We studied this in the mass-recruiting ant Lasius niger. We used mazes with two T-bifurcations, and allowed colonies to exploit two equidistant food sources that differed in how easily their locations were learned. In experiment 1, learnability was manipulated by using repeating versus alternating routes from nest to feeder. In experiment 2, we added visual landmarks along the route to one food source. Our results suggest that colonies preferentially exploited the feeding site that was easier to learn. This was the case even if the more difficult to learn feeding site was discovered first. Furthermore, we show that these preferences were at least partly caused by lower error rates (experiment 1) and greater foraging speeds (experiment 2) of foragers visiting the more easily learned feeder locations. Our results indicate that the learnability of feeding sites is an important factor influencing collective foraging patterns of ant colonies under more natural conditions, given that in natural environments foragers often face multiple bifurcations on their way to food sources.

Training primary care physicians in shared decision making for colorectal cancer screening : Insights from the first statewide colorectal cancer screening program in Switzerland

Background: The State of Vaud has launched the first population-based, organized, colorectal cancer screening program in Switzerland for the population aged 50 to 69. Each primary care physician (PCP) has been invited to participate in an interactive session preparing them to enroll patients in the screening program. We aimed at testing the impact of an interactive seminar for PCPs on their intention to discuss the options of no screening, screening with the fecal-immunological test (FIT) and colonoscopy. We measured attitude, intentions and knowledge through questionnaires filled by PCPs before and after a 2.5 hour-long interactive seminar. The main outcome was the proportion of physicians foreseeing to offer coloscopy vs FIT on an equal basis. Physicians estimated the proportion of their patients prescribed a fecal occult blood test (FOBT) vs coloscopy over the months before the seminar and after the interactive seminar. We used a clinical vignette to test for knowledge about screening indications. The interactive seminar included powerpoint presentations with quizzes and clickers, an 8-minute video presenting a shared decision making (SDM) consultation around CRC screening and distribution of educational materials such as a SDM decision aid and background epidemiological information.

A method for decision making with the OWA operator

A new method for decision making that uses the ordered weighted averaging (OWA) operator in the aggregation of the information is presented. It is used a concept that it is known in the literature as the index of maximum and minimum level (IMAM). This index is based on distance measures and other techniques that are useful for decision making. By using the OWA operator in the IMAM, we form a new aggregation operator that we call the ordered weighted averaging index of maximum and minimum level (OWAIMAM) operator. The main advantage is that it provides a parameterized family of aggregation operators between the minimum and the maximum and a wide range of special cases. Then, the decision maker may take decisions according to his degree of optimism and considering ideals in the decision process. A further extension of this approach is presented by using hybrid averages and Choquet integrals. We also develop an application of the new approach in a multi-person decision-making problem regarding the selection of strategies.

Cooperation versus competition effects on information sharing and use in group decision making

Information processing in groups has long been seen as a cooperative process. In contrast with this assumption, group members were rarely found to behave cooperatively: They withhold unshared information and stick to initial incorrect decisions. In the present article, we examined how group members' cooperative and competitivemotives impact on group information processing and propose that information sharing and use in groups could be seen as strategic behavior. We reviewed the latest developments in the literature investigating different forms of strategic information processing and their underlying mechanisms. This review suggests that explicit cooperative goals are needed for effective group decision-making.

Regression-based techniques for statistical decision making in single-case designs

The present study evaluates the performance of four methods for estimating regression coefficients used to make statistical decisions regarding intervention effectiveness in single-case designs. Ordinary least squares estimation is compared to two correction techniques dealing with general trend and one eliminating autocorrelation whenever it is present. Type I error rates and statistical power are studied for experimental conditions defined by the presence or absence of treatment effect (change in level or in slope), general trend, and serial dependence. The results show that empirical Type I error rates do not approximate the nominal ones in presence of autocorrelation or general trend when ordinary and generalized least squares are applied. The techniques controlling trend show lower false alarm rates, but prove to be insufficiently sensitive to existing treatment effects. Consequently, the use of the statistical significance of the regression coefficients for detecting treatment effects is not recommended for short data series.

Clinical utility of a molecular test in adjuvant treatment decision making in women with endocrine-sensitive early stage breast cancer: a retrospective, single center one year experience

Background. Molecular tests for breast cancer (BC) risk assessment are reimbursed by health insurances in Switzerland since the beginning of year 2015. The main current role of these tests is to help oncologists to decide about the usefulness of adjuvant chemotherapy in patients with early stage endocrine-sensitive and human epidermal growth factor receptor 2 (HER2)-negative BC. These gene expression signatures aim at predicting the risk of recurrence in this subgroup. One of them (OncotypeDx/OT) also predicts distant metastases rate with or without the addition of cytotoxic chemotherapy to endocrine therapy. The clinical utility of these tests -in addition to existing so-called "clinico-pathological" prognostic and predictive criteria (e.g. stage, grade, biomarkers status)-is still debated. We report a single center one year experience of the use of one molecular test (OT) in clinical decision making. Methods. We extracted from the CHUV Breast Cancer Center data base the total number of BC cases with estrogen-receptor positive (ER+), HER2-negative early breast cancer (node negative (pN0) disease or micrometastases in up to 3 lymph nodes) operated between September 2014 and August 2015. For the cases from this group in which a molecular test had been decided by the tumor board, we collected the clinicopathologic parameters, the initial tumor board decision, and the final adjuvant systemic therapy decision. Results. A molecular test (OT) was done in 12.2% of patients with ER + HER2 negative early BC. The median age was 57.4 years and the median invasive tumor size was 1.7 cm. These patients were classified by ODX testing (Recurrence Score) into low-, intermediate-, and high risk groups, respectively in 27.2%, 63.6% and 9% of cases. Treatment recommendations changed in 18.2%, predominantly from chemotherapyendocrine therapy to endocrine treatment alone. Of 8 patients originally recommended chemotherapy, 25% were recommended endocrine treatment alone after receiving the Recurrence Score result. Conclusions. Though reimbursed by health insurances since January 2015, molecular tests are used moderately in our institution as per the decision of the multidisciplinary tumor board. It's mainly used to obtain a complementary confirmation supporting the decision of no chemotherapy. The OncotypeDx Recurrence Score results were in the intermediate group in 66% of the 9 tested cases but contributed to avoid chemotherapy in 2 patients during the last 12 months.

Programme cantonal vaudois de dépistage du cancer colorectal: information et décision partagée [Shared decision making in the colorectal cancer screening program in the canton of Vaud].

Le programme cantonal vaudois de dépistage du cancer colorectal vise à faciliter ce dépistage pour la population de 50 à 69 ans. Les deux modalités retenues sont la recherche immunologique de sang dans les selles (FIT) et la coloscopie. La décision de réaliser un test de dépistage et la modalité de dépistage s'appuient sur une consultation individuelle avec un médecin de famille. L'assurance de base prend en charge le remboursement. Le programme vaudois permet l'exemption de la franchise pour la consultation médicale d'information et les deux modalités de dépistage, ainsi que pour la coloscopie de confirmation en cas de test FIT positif. La quote-part de 10 % reste à charge des participants. Des outils de communication ont été développés pour faciliter un entretien de décision partagée dans le cadre d'une consultation médicale. The colorectal cancer screening program of the canton of Vaud aims to facilitate screening for this cancer for the population aged 50 to 69 years old. The two screening modalities offered are fecal immunochemical testing (FIT) and colonoscopy. The decision to undergo screening and the screening modality is based on an individual medical encounter with a primary care physician. Both screening modalities are reimbursed through basic health coverage in Switzerland. The participation to the screening program allows the exemption of the deductible for the medical encounter and the chosen screening modality. A copay of 10% is maintained for all costs. Communication tools were developed on the basis of recommendations in the literature to facilitate shared decision-making in a medical encounter.

Identification of imaging selection patterns in acute ischemic stroke patients and the influence on treatment and clinical trial enrollment decision making.

BACKGROUND AND PURPOSE: For the STroke Imaging Research (STIR) and VISTA-Imaging Investigators The purpose of this study was to collect precise information on the typical imaging decisions given specific clinical acute stroke scenarios. Stroke centers worldwide were surveyed regarding typical imaging used to work up representative acute stroke patients, make treatment decisions, and willingness to enroll in clinical trials. METHODS: STroke Imaging Research and Virtual International Stroke Trials Archive-Imaging circulated an online survey of clinical case vignettes through its website, the websites of national professional societies from multiple countries as well as through email distribution lists from STroke Imaging Research and participating societies. Survey responders were asked to select the typical imaging work-up for each clinical vignette presented. Actual images were not presented to the survey responders. Instead, the survey then displayed several types of imaging findings offered by the imaging strategy, and the responders selected the appropriate therapy and whether to enroll into a clinical trial considering time from onset, clinical presentation, and imaging findings. A follow-up survey focusing on 6 h from onset was conducted after the release of the positive endovascular trials. RESULTS: We received 548 responses from 35 countries including 282 individual centers; 78% of the centers originating from Australia, Brazil, France, Germany, Spain, United Kingdom, and United States. The specific onset windows presented influenced the type of imaging work-up selected more than the clinical scenario. Magnetic Resonance Imaging usage (27-28%) was substantial, in particular for wake-up stroke. Following the release of the positive trials, selection of perfusion imaging significantly increased for imaging strategy. CONCLUSIONS: Usage of vascular or perfusion imaging by Computed Tomography or Magnetic Resonance Imaging beyond just parenchymal imaging was the primary work-up (62-87%) across all clinical vignettes and time windows. Perfusion imaging with Computed Tomography or Magnetic Resonance Imaging was associated with increased probability of enrollment into clinical trials for 0-3 h. Following the release of the positive endovascular trials, selection of endovascular only treatment for 6 h increased across all clinical vignettes.