Are we over-estimating the value of further research? A review of methods used to estimate uptake in population expected value of information analyses

Background: There is a lack of guidance on how population estimates should be obtained for expected value of information (EVI) analysis. We argue that disregarding uptake may lead to over-estimation of the population EVI (PEVI). Aims: To investigate how population estimates for PEVI analyses were obtained, whether they were adjusted by uptake and what methods were employed to obtain the uptake estimates. Methods: A literature search and review was conducted using the NHS Economic Evaluation Database (EED) and prior knowledge of relevant publications. Publications were excluded when they did not report PEVI estimates or were duplicates. Results: Out of 43 records resulting from the CRD search and 3 relevant publications that were known to us prior to this study, 29 studies were included. Out of these, 27 had not adjusted their population estimate by uptake levels. The remaining 2 studies had obtained their uptake estimates from uptake levels reported in trials and based on assumption. Only 5 studies acknowledged uncertainty associated with the population estimate used. Conclusion: Based on the result that very few PEVI studies had adjusted their population estimate by uptake and taking into account the large downward effect that uptake adjustments could have on the value of PEVI estimates, there is a need for discussion and further research around uptake adjustments in PEVI analyses

When future change matters: modelling future price and diffusion in health technology assessments of medical devices

Objectives: Whilst health technology assessments (HTAs) that take account of future price change have been examined in the literature, the important issue of price reductions that are generated by the reimbursement decision has been ignored. Our objective is to explore the impact of future price reductions caused by increasing uptake on HTAs and decision making for medical devices. Methods: We demonstrate the use of a two-stage modelling approach to derive estimates of technology price as a consequence of changes in technology uptake over future periods based on existing theory and supported by empirical studies. We explore the impact on cost-effectiveness and expected value of information analysis in an illustrative example based on a technology used in pre-term birth screening that is in development. Results: The application of our approach to the case study technology generates smaller incremental cost-effectiveness ratios (ICERs) compared to the commonly used single cohort approach. The extent of this reduction of the ICER depends on the magnitude of the modelled price reduction, the speed of diffusion and the length of the assumed technology-life horizon. Results of value of information analysis are affected through changes in the expected net benefit calculation, the addition of uncertain parameters and the diffusion-adjusted estimate of the affected patient population. Conclusions: Since modelling future changes in price and uptake has the potential to affect HTA outcomes, modelling techniques that can address such changes should be considered for medical devices that may otherwise be rejected

Assessing the expected value of research resolving uncertainty and improving implementation

Background: With low implementation of cost-effective health technologies being a problem in many health systems, it may be worth considering the potential effect of research on implementation at the time of technology appraisal. Objective: To demonstrate methods for assessing the value of research in terms of both reduction of uncertainty and improvement in implementation, considering the dynamic nature of implementation. Methods: We extend an existing framework to assess the values of information and implementation to account for the relationship between information and implementation and to reflect implementation dynamics. The resulting framework is applied to a genuine technology in the area of pre-term birth screening and results obtained from static and dynamic analyses are compared. The data to inform the effect of research evidence on implementation dynamics was obtained through a previous elicitation of expert opinion on quantities that informed the parameterisation of a dynamic implementation curve based on diffusion theory. Results: Incorporating the relationship between information and implementation in the assessment of research led to an expected value of research much larger than the one based on reduction of uncertainty alone in the exemplar case study. Considering the dynamics of implementation makes a significant difference to the expected value of research and accounting for the time when research reports may do so as well, both making existing analyses more realistic. However, such analyses require additional data and therefore resources. Conclusions: Assessing the expected value of research in terms of both, the reduction in uncertainty and improvements in implementation dynamics, has the potential to complement currently used analyses in health technology assessments, especially in Recommendation with Research decision

Estimating future health technology diffusion using expert beliefs calibrated to an established diffusion model

Objectives: Estimates of future health technology diffusion, or future uptake over time, are a requirement for different analyses performed within health technology assessments. Methods for obtaining such estimates include constant uptake estimates based on expert opinion or analogous technologies, and extrapolation from initial data points using parametric curves – but remain divorced from established diffusion theory and modelling. We propose an approach to obtaining diffusion estimates using experts’ beliefs calibrated to an established diffusion model to address this methodological gap. Methods: We performed an elicitation of experts’ beliefs on future diffusion of a new preterm birth screening illustrative case study technology. The elicited quantities were chosen such that they could be calibrated to yield the parameters of the Bass model of new product growth, which was chosen based on a review of the diffusion literature. Results: With the elicitation of only three quantities per diffusion curve, our approach enabled us to quantify uncertainty about diffusion of the new technology in different scenarios. Pooled results showed that the attainable number of adoptions was predicted to be relatively low compared with what was thought possible. Further research evidence improved the attainable number of adoptions only slightly but resulted in greater speed of diffusion. Conclusions: The proposed approach of eliciting experts’ beliefs about diffusion and informing the Bass model has the potential to fill the methodological gap evident in value of implementation and research, as well as budget impact and some cost-effectiveness analyses

Scaling up local energy infrastructure; An agent-based model of the emergence of district heating networks

The potential contribution of local energy infrastructure – such as heat networks – to the transition to a low carbon economy is increasingly recognised in international, national and municipal policy. Creating the policy environment to foster the scaling up of local energy infrastructure is, however, still challenging; despite national policy action and local authority interest the growth of heat networks in UK cities remains slow. Technoeconomic energy system models commonly used to inform policy are not designed to address institutional and governance barriers. We present an agent-based model of heat network development in UK cities in which policy interventions aimed at the institutional and governance barriers faced by diverse actors can be explored. Three types of project instigators are included – municipal, commercial and community – which have distinct decision heuristics and capabilities and follow a multi-stage development process. Scenarios of policy interventions developed in a companion modelling approach indicate that the effect of interventions differs between actors depending on their capabilities. Successful interventions account for the specific motivations and capabilities of different actors, provide a portfolio of support along the development process and recognise the important strategic role of local authorities in supporting low carbon energy infrastructure

Development and Validation of the TRansparent Uncertainty ASsessmenT (TRUST) Tool for Assessing Uncertainties in Health Economic Decision Models.

Background An increasing number of technologies are obtaining marketing authorisation based on sparse evidence, which causes growing uncertainty and risk within health technology reimbursement decision making. To ensure that uncertainty is considered and addressed within health technology assessment (HTA) recommendations, uncertainties need to be identifed, included in health economic models, and reported. Objective Our objective was to develop the TRansparent Uncertainty ASsessmenT (TRUST) tool for systematically identifying, assessing, and reporting uncertainties in decision models, with the aim of making uncertainties and their impact on cost efectiveness more explicit and transparent. Methods TRUST was developed by drawing on the uncertainty and risk assessment literature. To develop and validate this tool, we conducted HTA stakeholder discussion meetings and interviews and applied it in six real-world HTA case studies in the Netherlands and the UK. Results The TRUST tool enables the identifcation and categorisation of uncertainty according to its source (transparency issues, methodology issues, and issues with evidence: imprecision, bias and indirectness, and unavailability) in each model aspect. The source of uncertainty determines the appropriate analysis. The impact of uncertainties on cost efectiveness is also assessed. Stakeholders found using the tool to be feasible and of value for transparent uncertainty assessment. TRUST can be used during model development and/or model review. Conclusion The TRUST tool enables systematic identifcation, assessment, and reporting of uncertainties in health economic models and may contribute to more informed and transparent decision making in the face of uncertainty

Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering

We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 = 0.15, 0.25 (GeV/c)^2. The results are inconsistent with calculations solely using the elastic nucleon intermediate state, and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A_n provides a direct probe of the imaginary component of the 2-gamma exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.Comment: 5 pages, 3 figures, submitted to Physical Review Letters; shortened to meet PRL length limit, clarified some text after referee's comment

Strange Quark Contributions to Parity-Violating Asymmetries in the Forward G0 Electron-Proton Scattering Experiment

We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < Q^2 < 1.0 GeV^2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange quark contributions to the currents of the proton. The measurements were made at JLab using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate non-zero, Q^2 dependent, strange quark contributions and provide new information beyond that obtained in previous experiments.Comment: 5 pages, 2 figure

The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles

In the G0 experiment, performed at Jefferson Lab, the parity-violating elastic scattering of electrons from protons and quasi-elastic scattering from deuterons is measured in order to determine the neutral weak currents of the nucleon. Asymmetries as small as 1 part per million in the scattering of a polarized electron beam are determined using a dedicated apparatus. It consists of specialized beam-monitoring and control systems, a cryogenic hydrogen (or deuterium) target, and a superconducting, toroidal magnetic spectrometer equipped with plastic scintillation and aerogel Cerenkov detectors, as well as fast readout electronics for the measurement of individual events. The overall design and performance of this experimental system is discussed.Comment: Submitted to Nuclear Instruments and Method

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters