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Prior Elicitation
Published in Emmanuel Lesaffre, Gianluca Baio, Bruno Boulanger, Bayesian Methods in Pharmaceutical Research, 2020
Nicky Best, Nigel Dallow, Timothy Montague
The resulting fitted prior is then a mixture of the fitted distributions for (i) and (ii) with mixture weights given by (iii). Dallow et al. (2018) discuss the use of this bimodal elicitation technique to address potential problems of over-optimism when eliciting expert beliefs about the true treatment effect for new medicine. In the early phases of drug development, there is often a reasonable probability that the drug being tested will demonstrate no efficacy in the planned endpoint of interest, but it may be scientifically implausible that it will have a true negative effect. Such beliefs can be hard to capture via a single unimodal prior distribution, so Dallow et al. provide an example where they first elicit the expert's probability, w, that the drug has a true positive/favorable effect, and then elicit the distribution of this effect size conditional on the assumption that the drug does have a favorable effect. They then construct a bimodal prior for the drug response as a weighted mixture of the prior for the placebo or control response (which had been elicited separately), with weight (1 − w), and the conditional distribution for the drug effect given that the drug works, with weight w (see Figure 5.2).
Introduction
Published in Mani Lakshminarayanan, Fanni Natanegara, Bayesian Applications in Pharmaceutical Development, 2019
Mani Lakshminarayanan, Fanni Natanegara
One may prefer to provide prior information on the Odds Ratio OR = exp(β) scale and mathematically transform back to the logit scale. Alternative approaches include deriving prior distributions for various categories or using a prior elicitation technique. Assuming a normal prior, , Bayes theorem can be used to derive the posterior as follows.
Visual media in educational research
Published in Louis Cohen, Lawrence Manion, Keith Morrison, Research Methods in Education, 2017
Louis Cohen, Lawrence Manion, Keith Morrison
In the photo-elicitation technique, the photograph, or set of photographs, or sequence of photographs, is used to invoke, prompt and promote discussion, reflections, comments, observations and memories (Banks, 2007, p. 65). The interview or meeting between the researcher and participant(s) can start with photographs, what they show, who took them, when, where, what is the story behind them, and so on. Photographs can break down differentials of power between the researcher and participants (Prosser and Burke, 2011; Pyle, 2012; Torre and Murphy, 2015).
Methodological similarities and variations among EQ-5D-5L value set studies: a systematic review
Published in Journal of Medical Economics, 2022
N. Poudel, S. M. Fahim, J. Qian, K. Garza, N. Chaiyakunapruk, S. Ngorsuraches
A Microsoft Excel spreadsheet was developed to include the extracted data and was verified by the second reviewer (SMF). The Excel spreadsheet contained information regarding (1) general study characteristics – (a) sample: sampling method, number of responses analyzed, and (b) data collection: training for the interviewer, mode of data collection, EuroQol Valuation Technique (EQ-VT) used, QC procedure, hypothetical state (HS) versus own health state/experience (EB) approach used; (2) preference elicitation technique – (a) design: types of TTO, types of DCE, types of visual analog scales (VAS), number of valuation choices per respondent in each design, and (b) modeling approach: model used to derive value set; and (3) value set modeling – final model used to derive value set. Also, the reported value set and standard error for each country were extracted.
Reliability, construct validity, and responsiveness of the neck disability index and numeric pain rating scale in patients with mechanical neck pain without upper extremity symptoms
Published in Physiotherapy Theory and Practice, 2019
Ian A. Young, James Dunning, Raymond Butts, Firas Mourad, Joshua A. Cleland
In patients with MNP, the minimum detectable change (MDC) for the NDI has been reported to be: 19.6 (Cleland, Childs, and Whitman, 2008); 8.4 (Jorritsma et al., 2012); 10.2 (Young et al., 2009) 4.2 (Westaway, Stratford, and Binkley, 1998); and 5.0 (Stratford et al., 1999); whereas the reported MCID values are: 19 (Cleland, Childs, and Whitman, 2008); 3.5 (Jorritsma et al., 2012); 7.5 (Young et al., 2009); and 5.0 (Stratford et al., 1999) percentage points. The NDI has demonstrated fair (ICC = 0.50] (Cleland, Childs, and Whitman, 2008), moderate [ICC = 0.64] (Young et al., 2009), and excellent test-retest reliability [ICC = 0.86] (Jorritsma et al., 2012), r = 0.89 (Vernon and Mior, 1991), r = 0.94 (Stratford et al., 1999), r = 0.96 (Shaheen, Omar, and Vernon, 2013) in patients with MNP. In addition, the NDI has been found to possess strong/excellent construct validity in patients with MNP when compared with: Global Rating of Change r = 0.52 (Young et al., 2009) and r = 0.81 (Shaheen, Omar, and Vernon, 2013); Neck Bournemouth Questionnaire pretreatment 0.80 (Gay, Madson, and Cieslak, 2007) and post-treatment 0.77; Neck Pain and Disability Scale r = 0.86 (En, Clair, and Edmondston, 2009); and Problem Elicitation Technique r = 0.62 (En, Clair, and Edmondston, 2009).
Mothers’ experiences of settling infants in central Vietnam “through their eyes”: A photo-elicitation study
Published in Health Care for Women International, 2019
Linda Murray, Nicole McDonald, Vo Van Thang
We used a participatory photo-elicitation technique as well as in-depth interviews to gain insight into mothers’ experiences of explaining and responding to unsettled infant behavior. Photo-elicitation is a research method “based on the simple idea of inserting a photograph into a research interview” and uses visual data (photographs) to enrich the research process (Harper, 2002). Participatory photo elicitation involves photographs taken by research participants themselves as a form of qualitative data, and uses such photographs as points of discussion during verbal in-depth interviews. This can assist with building trust between participants and researchers, and also as a means of assisting participants to communicate their perspective (Fleury, Keller & Perez, 2009; Hurworth, Clark, Martin, & Thomsen, 2005). Photo-elicitation emerged from the work of John Collier and others, who found that using photographs during interviews provided “conduits to narratives” as visual images can elicit memories and information about the content of the image that would not be discussed in a traditional verbal interview (Fleury et al., 2009).