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

Shear horizontal (SH) ultrasound wave propagation around smooth corners

AbstractShear horizontal (SH) ultrasound guided waves are being used in an increasing number of non-destructive testing (NDT) applications. One advantage SH waves have over some wave types, is their ability to propagate around curved surfaces with little energy loss; to understand the geometries around which they could propagate, the wave reflection must be quantified. A 0.83mm thick aluminium sheet was placed in a bending machine, and a shallow bend was introduced. Periodically-poled magnet (PPM) electromagnetic acoustic transducers (EMATs), for emission and reception of SH waves, were placed on the same side of the bend, so that reflected waves were received. Additional bending of the sheet demonstrated a clear relationship between bend angles and the reflected signal. Models suggest that the reflection is a linear superposition of the reflections from each bend segment, such that sharp turns lead to a larger peak-to-peak amplitude, in part due to increased phase coherence

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

Family Unification in Five and Six Dimensions

In family unification models, all three families of quarks and leptons are grouped together into an irreducible representation of a simple gauge group, thus unifying the Standard Model gauge symmetries and a gauged family symmetry. Large orthogonal groups, and the exceptional groups $E_7$ and $E_8$ have been much studied for family unification. The main theoretical difficulty of family unification is the existence of mirror families at the weak scale. It is shown here that family unification without mirror families can be realized in simple five-dimensional and six-dimensional orbifold models similar to those recently proposed for SU(5) and SO(10) grand unification. It is noted that a family unification group that survived to near the weak scale and whose coupling extrapolated to high scales unified with those of the Standard model would be evidence accessible in principle at low energy of the existence of small (Planckian or GUT-scale) extra dimensions.Comment: 13 pages, 2 figures, minor corrections, references adde

Meaningful time for professional growth or a waste of time? A study in five countries on teachers’ experiences within master’s dissertation/thesis work

The relationship between master’s thesis work and teachers’ professional development has rarely been explored empirically, yet. Drawing upon a larger study, this paper investigates how teachers who were studying for or who have recently graduated from Master of Education programmes offered in five countries – Poland, Portugal, England, Latvia, Romania – perceive the usefulness of dissertation/thesis work for their professional development and how they attempt to use their MA research results in their (future) teaching practice. Results suggest that although most respondents recognized their MA dissertation/thesis work as having a positive impact on their professional development by enhancing their professionalism, personal development and growth, and understanding the relationship between research and practice, they were less confident about the use of MA research findings in their (future) workplaces. These results are discussed in the context of current challenges regarding master’s level education for teachers, national governments’ educational policies, and the relationship between research, teachers’ practices and professional development

Electronic structure of nuclear-spin-polarization-induced quantum dots

We study a system in which electrons in a two-dimensional electron gas are confined by a nonhomogeneous nuclear spin polarization. The system consists of a heterostructure that has non-zero nuclei spins. We show that in this system electrons can be confined into a dot region through a local nuclear spin polarization. The nuclear-spin-polarization-induced quantum dot has interesting properties indicating that electron energy levels are time-dependent because of the nuclear spin relaxation and diffusion processes. Electron confining potential is a solution of diffusion equation with relaxation. Experimental investigations of the time-dependence of electron energy levels will result in more information about nuclear spin interactions in solids

Crystal and electronic structures of A2NaIO6 periodate double perovskites (A = Sr, Ca, Ba): candidate wasteforms for I-129 immobilization

The synthesis, structure, and thermal stability of the periodate double perovskites A2NaIO6 (A= Ba, Sr, Ca) were investigated in the context of potential application for the immobilization of radioiodine. A combination of X-ray diffraction and neutron diffraction, Raman spectroscopy, and DFT simulations were applied to determine accurate crystal structures of these compounds and understand their relative stability. The compounds were found to exhibit rock-salt ordering of Na and I on the perovskite B-site; Ba2NaIO6 was found to adopt the Fm-3m aristotype structure, whereas Sr2NaIO6 and Ca2NaIO6 adopt the P21/n hettotype structure, characterized by cooperative octahedral tilting. DFT simulations determined the Fm-3m and P21/n structures of Ba2NaIO6 to be energetically degenerate at room temperature, whereas diffraction and spectroscopy data evidence only the presence of the Fm-3m phase at room temperature, which may imply an incipient phase transition for this compound. The periodate double perovskites were found to exhibit remarkable thermal stability, with Ba2NaIO6 only decomposing above 1050 °C in air, which is apparently the highest recorded decomposition temperature so far recorded for any iodine bearing compound. As such, these compounds offer some potential for application in the immobilization of iodine-129, from nuclear fuel reprocessing, with an iodine incorporation rate of 25–40 wt%. The synthesis of these compounds, elaborated here, is also compatible with both current conventional and future advanced processes for iodine recovery from the dissolver off-gas