983 research outputs found

    Can groups improve expert economic and financial forecasts?

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    Economic and financial forecasts are important for business planning and government policy but are notoriously challenging. We take advantage of recent advances in individual and group judgement, and a data set of economic and financial forecasts compiled over 25 years, consisting of multiple individual and institutional estimates, to test the claim that nominal groups will make more accurate economic and financial forecast than individuals. We validate the forecasts using the subsequent published (real) outcomes, explore the performance of nominal groups against institutions, identify potential superforecasters and discuss the benefits of implementing structured judgment techniques to improve economic and financial forecasts

    Improving expert forecasts in reliability. Application and evidence for structured elicitation protocols

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    Quantitative expert judgementsare used in reliability assessmentsto informcritically important decisions. Structured elicitation protocols have been advocated to improveexpert judgements, yet their application in reliability ischallenged by a lack of examples or evidence that they improve judgements. This paper aims to overcome these barriers. We present a case study where two world-leading protocols, the IDEA protocol and the Classical Model were combined and applied by the Australian Department of Defence for a reliability assessment. We assess the practicality of the methods, and the extent to which they improve judgements. The average expert was extremely overconfident, with 90% credible intervals containing the true realisation 36% of the time. However,steps contained inthe protocols substantially improvedjudgements. In particular, an equal weighted aggregation of individual judgements, and the inclusion ofa discussion phase and revised estimate helped to improve calibration, statistical accuracy and the Classical Model score. Further improvements in precision and information were made via performance weighted aggregation. This paper provides useful insights into the application of structured elicitation protocols for reliability andthe extent to which judgements are improved. The findings raise concerns about existing practices for utilising experts in reliability assessments and suggest greater adoption of structured protocols is warranted. We encourage the reliability community to further develop examples and insights

    The value of performance weights and discussion in aggregated expert judgements

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    In risky situations characterized by imminent decisions, scarce resources, and insufficient data, policymakers rely on experts to estimate model parameters and their associated uncertainties. Different elicitation and aggregation methods can vary substantially in their efficacy and robustness. While it is generally agreed that biases in expert judgments can be mitigated using structured elicitations involving groups rather than individuals, there is still some disagreement about how to best elicit and aggregate judgments. This mostly concerns the merits of using performance‐based weighting schemes to combine judgments of different individuals (rather than assigning equal weights to individual experts), and the way that interaction between experts should be handled. This article aims to contribute to, and complement, the ongoing discussion on these topics

    Protecting biodiversity and economic returns in resource rich tropical forests

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    In pursuit of socioeconomic development, many countries are expanding oil and mineral extraction into tropical forests. These activities seed access to remote, biologically rich areas, thereby endangering global biodiversity. Here we demonstrate that conservation solutions that effectively balance the protection of biodiversity and economic revenues are possible in biologically valuable regions. Using spatial data on oil profits and predicted species and ecosystem extents, we optimise the protection of 741 terrestrial species and 20 ecosystems of the Ecuadorian Amazon, across a range of opportunity costs (i.e. sacrifices of extractive profit). For such an optimisation, giving up 5% of a year's oil profits (US221million)allowsforaprotectedareanetworkthatretainsofanaverageof65 221 million) allows for a protected area network that retains of an average of 65% of the extent of each species/ecosystem. This performance far exceeds that of the network produced by simple land area optimisation which requires a sacrifice of approximately 40% of annual oil profits (US 1.7 billion), and uses only marginally less land, to achieve equivalent levels of ecological protection. Applying spatial statistics to remotely sensed, historic deforestation data, we further focus the optimisation to areas most threatened by imminent forest loss. We identify Emergency Conservation Targets: areas that are essential to a cost‐effective conservation reserve network and at imminent risk of destruction, thus requiring urgent and effective protection. Governments should employ the methods presented here when considering extractive led development options, to responsibly manage the associated ecological‐economic trade‐offs and protect natural capital

    Facilitating the transition to sustainable green chemistry

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    Sustainable green chemistry depends on technically feasible, cost-effective and socially acceptable decisions by regulators, industry and the wider community. The discipline needs to embrace a new suite of tools and train proponents in their use. We propose a set of tools that will bridge the gap between technical feasibility and efficiency on one hand, and social preferences and values on the other. We argue that they are indispensable in the next generation of regulators and chemistry industry proponents

    Robust decision-making under severe uncertainty for conservation management

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    In-conservation biology it is necessary to make management decisions for endangered and threatened species under severe uncertainty. Failure to acknowledge and treat uncertainty can lead to poor decisions. To illustrate the importance of considering uncertainty, we reanalyze a decision problem for the Sumatran rhino, Dicerorhinus sumatrensis, using information-gap theory to propagate uncertainties and to rank management options. Rather than requiring information about the extent of parameter uncertainty at the outset, information-gap theory addresses the question of how much uncertainty can be tolerated before our decision would change. It assesses the robustness of decisions in the face of severe uncertainty. We show that different management decisions may result when uncertainty in utilities and probabilities are considered in decision-making problems. We highlight the importance of a full assessment of uncertainty in conservation management decisions to avoid, as much as possible, undesirable outcomes

    Change in CD3 positive T-cell expression in psoriatic arthritis synovium correlates with change in DAS28 and magnetic resonance imaging synovitis scores following initiation of biologic therapy - a single centre, open-label study

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    With the development of increasing numbers of potential therapeutic agents in inflammatory disease comes the need for effective biomarkers to help screen for drug efficacy and optimal dosing regimens early in the clinical trial process. This need has been recognized by the Outcome Measures in Rheumatology Clinical Trials (OMERACT) group, which has established guidelines for biomarker validation. To seek a candidate synovial biomarker of treatment response in psoriatic arthritis (PsA), we determined whether changes in immunohistochemical markers of synovial inflammation correlate with changes in disease activity scores assessing 28 joints (ΔDAS28) or magnetic resonance imaging synovitis scores (ΔMRI) in patients with PsA treated with a biologic agent. Twenty-five consecutive patients with PsA underwent arthroscopic synovial biopsies and MRI scans of an inflamed knee joint at baseline and 12 weeks after starting treatment with either anakinra (first 10 patients) or etanercept (subsequent 15 patients) in two sequential studies of identical design. DAS28 scores were measured at both time points. Immunohistochemical staining for CD3, CD68 and Factor VIII (FVIII) was performed on synovial samples and scored by digital image analysis (DIA). MRI scans performed at baseline and at 12 weeks were scored for synovitis semi-quantitatively. The ΔDAS28 of the European League Against Rheumatism good response definition (>1.2) was chosen to divide patients into responder and non-responder groups. Differences between groups (Mann Whitney U test) and correlations between ΔDAS28 with change in immunohistochemical and MRI synovitis scores (Spearman's rho test) were calculated. Paired synovial samples and MRI scans were available for 21 patients (8 anakinra, 13 etanercept) and 23 patients (8 anakinra, 15 etanercept) respectively. Change in CD3 (ΔCD3) and CD68 expression in the synovial sublining layer (ΔCD68sl) was significantly greater in the disease responders compared to non-responders following treatment (P = 0.005 and 0.013 respectively). ΔCD3, but not ΔCD68 or ΔFVIII, correlated with both ΔDAS28 (r = 0.49, P = 0.025) and ΔMRI (r = 0.58, P = 0.009). The correlation of ΔCD3 with ΔDAS28 and ΔMRI following biologic treatment in this cohort contributes to the validation of ΔCD3 as a synovial biomarker of disease response in PsA, and supports the further evaluation of ΔCD3 for predictive properties of future clinical outcome
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