The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Karl Claxton - One of the best experts on this subject based on the ideXlab platform.
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addressing adoption and research design decisions simultaneously the role of value of sample Information Analysis
Medical Decision Making, 2011Co-Authors: Claire Mckenna, Karl ClaxtonAbstract:Methods to estimate the cost-effectiveness of technologies are well developed with increasing experience of their application to inform adoption decisions in a timely way. However, the experience o...
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using value of Information Analysis to prioritise health research some lessons from recent uk experience
PharmacoEconomics, 2006Co-Authors: Karl Claxton, Mark SculpherAbstract:Decisions to adopt, reimburse or issue guidance on the use of health technologies are increasingly being informed by explicit cost-effectiveness analyses of the alternative interventions. Healthcare systems also invest heavily in research and development to support these decisions. However, the increasing transparency of adoption and reimbursement decisions, based on formal Analysis, contrasts sharply with research prioritisation and commissioning. This is despite the fact that formal measures of the value of evidence generated by research are readily available. The results of two recent opportunities to apply value of Information Analysis to directly inform policy decisions about research priorities in the UK are presented. These include a pilot study for the UK National Co-ordinating Centre for Health Technology Assessment (NCCHTA) and a pilot study for the National Institute for Health and Clinical Excellence (NICE). We demonstrate how these results can be used to address a series of policy questions, including: is further research required to support the use of a technology and, if so, what type of research would be most valuable? We also show how the results can be used to address other questions such as, which patient subgroups should be included in subsequent research, which comparators and endpoints should be included, and what length of follow up would be most valuable.
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a pilot study of value of Information Analysis to support research recommendations for the national institute for health and clinical excellence
2005Co-Authors: Karl Claxton, S Eggington, Laura Ginnelly, Susan Griffin, C Mccabe, Zoe Philips, Paul Tappenden, Alan WailooAbstract:Background - This project developed as a result of the activities of the Research Teams at the Centre for Health Economics, University of York, and ScHARR at the University of Sheffield in the methods and application of decision Analysis and value of Information Analysis as a means of informing the research recommendations made by NICE, as part of its Guidance to the NHS in England and Wales, and informing the deliberations of the NICE Research and Development Committee. Objectives - The specific objectives of the pilot study were to: • Demonstrate the benefits of using appropriate decision analytic methods and value of Information Analysis to inform research recommendations. • Establish the feasibility and resource implications of applying these methods in a timely way, to inform NICE. • Identify critical issues and methodological challenges to the use of value of Information methods for research recommendations (with particular regard to the new reference case as a suitable basis for this type of Analysis).
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a pilot study on the use of decision theory and value of Information Analysis as part of the nhs health technology assessment programme
Health Technology Assessment, 2004Co-Authors: Karl Claxton, Laura Ginnelly, Zoe Philips, Mark Sculpher, Stephen PalmerAbstract:OBJECTIVES To demonstrate the benefits of using appropriate decision-analytic methods and value of Information Analysis (DA-VOI). Also to establish the feasibility and implications of applying these methods to inform the prioritisation process of the NHS Health Technology Assessment (HTA) programme, and possibly extending their use therein. DATA SOURCES Three research topics that were considered by the HTA panels in the September 2002 and February 2003 prioritisation rounds. REVIEW METHODS A brief and non-technical overview of DA-VOI methods was circulated to the panels and Prioritisation Strategy Group (PSG). For each case study the results were presented to the panels and the PSG in the form of brief case-study reports. Feedback on the DA-VOI Analysis and its presentation was obtained in the form of completed questionnaires from panel members, and reports from panel senior lecturers and PSG members. RESULTS Although none of the research topics identified met all of the original selection criteria for inclusion as case studies in the pilot, it was possible to construct appropriate decision-analytic models and conduct probabilistic Analysis for each topic. In each case, the tasks were completed within the time-frame required by the existing HTA research prioritisation process. The brief case-study reports provided a description of the decision problem, a summary of the current evidence base and a characterisation of decision uncertainty in the form of cost-effectiveness acceptability curves. Estimates of value of Information for the decision problem were presented for relevant patient groups and clinical settings, as well as the value of Information associated with particular model inputs. The implications for the value of research in each of the areas were presented in general terms. Details were also provided on what the Analysis suggested regarding the design of any future research in terms of features such as the relevant patient groups and comparators, and whether experimental design was likely to be required. CONCLUSIONS The pilot study showed that, even with very short timelines, it is possible to undertake DA-VOI that can feed into the priority-setting process that has been developed for the HTA programme. There are however a number of areas that need to be established at the beginning of the process, such as clarification of the nature of the decision problem for which additional research is being considered, explicitness about which existing data should be used and how data that exhibit particular weaknesses should be down-weighted in the Analysis. Other areas, including optimum application of researcher time, integrating the vignette (a summary of the clinical problem and existing evidence) and the use of DA-VOI, training, use of sensitivity analyses, and deployment of clinical expertise, are also considered in terms of the potential implementation of DA-VOI within the HTA programme. Recommendations for further research include how literature searching should focus on those variables to which the model's results are most sensitive and with the highest expected value of perfect Information; methods of evidence synthesis (multiple parameter synthesis) to consider the evidence surrounding multiple comparators and networks of evidence; and ways in which the value of sample Information can be used by the NHS HTA programme and other research funders to decide on the most efficient design of new evaluative research. There is also a need for an analytical framework to be developed that can jointly address the question of whether additional resources would better be devoted to additional research or interventions to change clinical practice.
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bayesian value of Information Analysis an application to a policy model of alzheimer s disease
International Journal of Technology Assessment in Health Care, 2001Co-Authors: Karl Claxton, Peter J Neumann, Sally S Araki, Milton C WeinsteinAbstract:A framework is presented that distinguishes the conceptually separate decisions of which treatment strategy is optimal from the question of whether more Information is required to inform this choice in the future. The authors argue that the choice of treatment strategy should be based on expected utility, and the only valid reason to characterize the uncertainty surrounding outcomes of interest is to establish the value of acquiring additional Information. A Bayesian decision theoretic approach is demonstrated through a probabilistic Analysis of a published policy model of Alzheimer’s disease. The expected value of perfect Information is estimated for the decision to adopt a new pharmaceutical for the population of patients with Alzheimer’s disease in the United States. This provides an upper bound on the value of additional research. The value of Information is also estimated for each of the model inputs. This Analysis can focus future research by identifying those parameters where more precise estimates would be most valuable and indicating whether an experimental design would be required. We also discuss how this type of Analysis can also be used to design experimental research efficiently (identifying optimal sample size and optimal sample allocation) based on the marginal cost and marginal benefit of sample Information. Value-of-Information Analysis can provide a measure of the expected payoff from proposed research, which can be used to set priorities in research and development. It can also inform an efficient regulatory framework for new healthcare technologies: an Analysis of the value of Information would define when a claim for a new technology should be deemed substantiated and when evidence should be considered competent and reliable when it is not cost-effective to gather any more Information.
Oren Tsur - One of the best experts on this subject based on the ideXlab platform.
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local global contagion of viral non viral Information Analysis of contagion spread in online social networks
PLOS ONE, 2020Co-Authors: Alon Bartal, Nava Pliskin, Oren TsurAbstract:Contagion in online social networks (OSN) occurs when users are exposed to Information disseminated by other users. Studies of contagion are largely devoted to the spread of viral Information and to local neighbor-to-neighbor contagion. However, many contagion events can be non-viral in the sense of being unpopular with low reach size, or global in the sense of being exposed to non-adjacent neighbors. This study aims to investigate the differences between local and global contagion and the different contagion patterns of viral vs. non-viral Information. We analyzed three datasets and found significant differences between the temporal spreading patterns of local contagion compared to global contagion. Based on our Analysis, we can successfully predict whether a user will be infected by either a local or a global contagion. We achieve an F1-score of 0.87 for non-viral Information and an F1-score of 0.84 for viral Information. We propose a novel method for early detection of the viral potential of an Information nugget and investigate the spreading of viral and non-viral Information. In addition, we analyze both viral and non-viral contagion of a topic. Differentiating between local versus global contagion, as well as between viral versus non-viral Information, provides a novel perspective and better understanding of Information diffusion in OSNs.
Sheelagh Carpendale - One of the best experts on this subject based on the ideXlab platform.
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an exploratory study of visual Information Analysis
Human Factors in Computing Systems, 2008Co-Authors: Petra Isenberg, Anthony Tang, Sheelagh CarpendaleAbstract:To design Information visualization tools for collaborative use, we need to understand how teams engage with visualizations during their Information Analysis process. We report on an exploratory study of individuals, pairs, and triples engaged in Information Analysis tasks using paper-based visualizations. From our study results, we derive a framework that captures the Analysis activities of co-located teams and individuals. Comparing this framework with existing models of the Information Analysis process suggests that Information visualization tools may benefit from providing a flexible temporal flow of Analysis actions.
Stephen Palmer - One of the best experts on this subject based on the ideXlab platform.
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methods to identify postnatal depression in primary care an integrated evidence synthesis and value of Information Analysis
Health Technology Assessment, 2009Co-Authors: Catherine Hewitt, Stephen Palmer, Simon Gilbody, Stephen Brealey, Mike Paulden, Rachel Mann, Josephine M Green, Jane Morrell, Michael Barkham, Kate LightAbstract:Objectives To provide an overview of methods to identify postnatal depression (PND) in primary care and to assess their validity, acceptability, clinical effectiveness and cost-effectiveness, to model estimates of cost, to assess whether any method meets UK National Screening Committee (NSC) criteria and to identify areas for future research. Data sources Searches of 20 electronic databases (including MEDLINE, CINAHL, PsycINFO, EMBASE, CENTRAL, DARE and CDSR), forward citation searching, personal communication with authors and searching of reference lists. Review methods A generalised linear mixed model approach to the bivariate meta-Analysis was undertaken for the validation review with quality assessment using QUADAS. Within the acceptability review, a textual narrative approach was employed to synthesise qualitative and quantitative research evidence. For the clinical and cost-effectiveness reviews methods outlined by the Centre for Reviews and Dissemination and the Cochrane Collaboration were followed. Probabilistic models were developed to estimate the costs associated with different identification strategies. Results The Edinburgh Postnatal Depression Scale (EPDS) was the most frequently explored instrument across all of the reviews. In terms of test performance, postnatally the EPDS performed reasonably well: sensitivity ranged from 0.60 (specificity 0.97) to 0.96 (specificity 0.45) for major depression only; from 0.31 (specificity 0.99) to 0.91 (specificity 0.67) for major or minor depression; and from 0.38 (specificity 0.99) to 0.86 (specificity 0.87) for any psychiatric disorder. Evidence from the acceptability review indicated that, in the majority of studies, the EPDS was acceptable to women and health-care professionals when women were forewarned of the process, when the EPDS was administered in the home, with due attention to training, with empathetic skills of the health visitor and due consideration to positive responses to question 10 about self-harm. Suggestive evidence from the clinical effectiveness review indicated that use of the EPDS, compared with usual care, may lead to reductions in the number of women with depression scores above a threshold. In the absence of existing cost-effectiveness studies of PND identification strategies, a decision-analytic model was developed. The results of the base-case Analysis suggested that use of formal identification strategies did not appear to represent value for money, based on conventional thresholds of cost-effectiveness used in the NHS. However, the scenarios considered demonstrated that this conclusion was primarily driven by the costs of false positives assumed in the base-case model. Conclusions In light of the results of our evidence synthesis and decision modelling we revisited the examination of PND screening against five of the NSC criteria. We found that the accepted criteria for a PND screening programme were not currently met. The evidence suggested that there is a simple, safe, precise and validated screening test, in principle a suitable cut-off level could be defined and that the test is acceptable to the population. Evidence surrounding clinical and cost-effectiveness of methods to identify PND is lacking.
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methods to identify postnatal depression in primary care an integrated evidence synthesis and value of Information Analysis
Health Technology Assessment, 2009Co-Authors: Catherine Hewitt, Stephen Palmer, Simon Gilbody, Stephen Brealey, Mike Paulden, Rachel Mann, Josephine M Green, Jane Morrell, Michael Barkham, Kate LightAbstract:Objectives To provide an overview of methods to identify postnatal depression (PND) in primary care and to assess their validity, acceptability, clinical effectiveness and cost-effectiveness, to model estimates of cost, to assess whether any method meets UK National Screening Committee (NSC) criteria and to identify areas for future research. Data sources Searches of 20 electronic databases (including MEDLINE, CINAHL, PsycINFO, EMBASE, CENTRAL, DARE and CDSR), forward citation searching, personal communication with authors and searching of reference lists. Review methods A generalised linear mixed model approach to the bivariate meta-Analysis was undertaken for the validation review with quality assessment using QUADAS. Within the acceptability review, a textual narrative approach was employed to synthesise qualitative and quantitative research evidence. For the clinical and cost-effectiveness reviews methods outlined by the Centre for Reviews and Dissemination and the Cochrane Collaboration were followed. Probabilistic models were developed to estimate the costs associated with different identification strategies. Results The Edinburgh Postnatal Depression Scale (EPDS) was the most frequently explored instrument across all of the reviews. In terms of test performance, postnatally the EPDS performed reasonably well: sensitivity ranged from 0.60 (specificity 0.97) to 0.96 (specificity 0.45) for major depression only; from 0.31 (specificity 0.99) to 0.91 (specificity 0.67) for major or minor depression; and from 0.38 (specificity 0.99) to 0.86 (specificity 0.87) for any psychiatric disorder. Evidence from the acceptability review indicated that, in the majority of studies, the EPDS was acceptable to women and health-care professionals when women were forewarned of the process, when the EPDS was administered in the home, with due attention to training, with empathetic skills of the health visitor and due consideration to positive responses to question 10 about self-harm. Suggestive evidence from the clinical effectiveness review indicated that use of the EPDS, compared with usual care, may lead to reductions in the number of women with depression scores above a threshold. In the absence of existing cost-effectiveness studies of PND identification strategies, a decision-analytic model was developed. The results of the base-case Analysis suggested that use of formal identification strategies did not appear to represent value for money, based on conventional thresholds of cost-effectiveness used in the NHS. However, the scenarios considered demonstrated that this conclusion was primarily driven by the costs of false positives assumed in the base-case model. Conclusions In light of the results of our evidence synthesis and decision modelling we revisited the examination of PND screening against five of the NSC criteria. We found that the accepted criteria for a PND screening programme were not currently met. The evidence suggested that there is a simple, safe, precise and validated screening test, in principle a suitable cut-off level could be defined and that the test is acceptable to the population. Evidence surrounding clinical and cost-effectiveness of methods to identify PND is lacking. Further research should aim to identify the optimal identification strategy, in terms of key psychometric properties for postnatal populations. In particular, research comparing the performance of the Whooley and help questions, the EPDS and a generic depression measure would be informative. It would also be informative to identify the natural history of PND over time and to identify the clinical effectiveness of the most valid and acceptable method to identify postnatal depression. Further research within a randomised controlled trial would provide robust estimates of the clinical effectiveness.
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a pilot study on the use of decision theory and value of Information Analysis as part of the nhs health technology assessment programme
Health Technology Assessment, 2004Co-Authors: Karl Claxton, Laura Ginnelly, Zoe Philips, Mark Sculpher, Stephen PalmerAbstract:OBJECTIVES To demonstrate the benefits of using appropriate decision-analytic methods and value of Information Analysis (DA-VOI). Also to establish the feasibility and implications of applying these methods to inform the prioritisation process of the NHS Health Technology Assessment (HTA) programme, and possibly extending their use therein. DATA SOURCES Three research topics that were considered by the HTA panels in the September 2002 and February 2003 prioritisation rounds. REVIEW METHODS A brief and non-technical overview of DA-VOI methods was circulated to the panels and Prioritisation Strategy Group (PSG). For each case study the results were presented to the panels and the PSG in the form of brief case-study reports. Feedback on the DA-VOI Analysis and its presentation was obtained in the form of completed questionnaires from panel members, and reports from panel senior lecturers and PSG members. RESULTS Although none of the research topics identified met all of the original selection criteria for inclusion as case studies in the pilot, it was possible to construct appropriate decision-analytic models and conduct probabilistic Analysis for each topic. In each case, the tasks were completed within the time-frame required by the existing HTA research prioritisation process. The brief case-study reports provided a description of the decision problem, a summary of the current evidence base and a characterisation of decision uncertainty in the form of cost-effectiveness acceptability curves. Estimates of value of Information for the decision problem were presented for relevant patient groups and clinical settings, as well as the value of Information associated with particular model inputs. The implications for the value of research in each of the areas were presented in general terms. Details were also provided on what the Analysis suggested regarding the design of any future research in terms of features such as the relevant patient groups and comparators, and whether experimental design was likely to be required. CONCLUSIONS The pilot study showed that, even with very short timelines, it is possible to undertake DA-VOI that can feed into the priority-setting process that has been developed for the HTA programme. There are however a number of areas that need to be established at the beginning of the process, such as clarification of the nature of the decision problem for which additional research is being considered, explicitness about which existing data should be used and how data that exhibit particular weaknesses should be down-weighted in the Analysis. Other areas, including optimum application of researcher time, integrating the vignette (a summary of the clinical problem and existing evidence) and the use of DA-VOI, training, use of sensitivity analyses, and deployment of clinical expertise, are also considered in terms of the potential implementation of DA-VOI within the HTA programme. Recommendations for further research include how literature searching should focus on those variables to which the model's results are most sensitive and with the highest expected value of perfect Information; methods of evidence synthesis (multiple parameter synthesis) to consider the evidence surrounding multiple comparators and networks of evidence; and ways in which the value of sample Information can be used by the NHS HTA programme and other research funders to decide on the most efficient design of new evaluative research. There is also a need for an analytical framework to be developed that can jointly address the question of whether additional resources would better be devoted to additional research or interventions to change clinical practice.
Alon Bartal - One of the best experts on this subject based on the ideXlab platform.
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local global contagion of viral non viral Information Analysis of contagion spread in online social networks
PLOS ONE, 2020Co-Authors: Alon Bartal, Nava Pliskin, Oren TsurAbstract:Contagion in online social networks (OSN) occurs when users are exposed to Information disseminated by other users. Studies of contagion are largely devoted to the spread of viral Information and to local neighbor-to-neighbor contagion. However, many contagion events can be non-viral in the sense of being unpopular with low reach size, or global in the sense of being exposed to non-adjacent neighbors. This study aims to investigate the differences between local and global contagion and the different contagion patterns of viral vs. non-viral Information. We analyzed three datasets and found significant differences between the temporal spreading patterns of local contagion compared to global contagion. Based on our Analysis, we can successfully predict whether a user will be infected by either a local or a global contagion. We achieve an F1-score of 0.87 for non-viral Information and an F1-score of 0.84 for viral Information. We propose a novel method for early detection of the viral potential of an Information nugget and investigate the spreading of viral and non-viral Information. In addition, we analyze both viral and non-viral contagion of a topic. Differentiating between local versus global contagion, as well as between viral versus non-viral Information, provides a novel perspective and better understanding of Information diffusion in OSNs.
