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Clinical Trials: the Statistician's Role
Published in Trevor F. Cox, Medical Statistics for Cancer Studies, 2022
One way to have more factors for balancing the two arms of the trial, is to use the method of minimisation. We show how the method works with a simple example. Suppose there are three factors to be used, F, G and H, each with two categories, “–” and “+”. As patients are recruited, they are allocated to arm A or arm B according to the numbers already in factor categories. Suppose five patients have been allocated to each of A and B and the numbers in the categories are as follows,
Introduction and Brief History of Structural Equation Modeling for Health and Medical Research
Published in Douglas D. Gunzler, Adam T. Perzynski, Adam C. Carle, Structural Equation Modeling for Health and Medicine, 2021
Douglas D. Gunzler, Adam T. Perzynski, Adam C. Carle
In conducting experimental research, the researcher maintains control over the environment (i.e. design and setting of the study) and is able to manipulate the boundaries on the primary independent variable. Experimental research is performed prospectively, and an intervention is tested in a regulated environment. For example, in a randomized, controlled clinical trial of a new sodium chloride tablet for patients with low sodium level, each patient is randomly assigned to receive the tablet or a placebo (a binary independent variable). The patients could be randomized into the treatment arm using stratification or minimization as well as a block design. As a result of the study design (and given a large enough sample), potential confounders such as age, gender and race should be approximately evenly distributed at least in theory between tablet and placebo group.
Critical appraisal of randomized clinical trials
Published in O. Ajetunmobi, Making Sense of Critical Appraisal, 2021
Minimisation is the most commonly used adaptive method of randomization. It involves identifying a few important prognostic factors in a trial and then applying a weighting system to them. Every subsequent subject is then randomized to the treatment group that would cause the least imbalance to the overall distribution of weighted prognostic factors between the compared groups. Minimization is performed in order to ensure an overall balance in the distribution of the more important prognostic factors between the various treatment groups of a trial.
Online learning versus workshops: a rank minimized trial comparing the effect of two knowledge translation strategies designed to alter knowledge, readiness to change, and self-efficacy with respect to rehabilitation outcome measures
Published in Disability and Rehabilitation, 2022
Mike Szekeres, Joy C. MacDermid
Subjects were allocated using minimization at each site, an allocation method that placed participants in intervention groups to minimize the differences across key predictors [16,17]. Minimization can be useful in small clinical trials where stratified randomization is not feasible because it can improve data utilization, simplify the statistical analysis, and reduce the risk of selection bias. The rationale is that minimization across key predictors helps to balance prognostic variables and result in more valid comparisons and has been shown to be superior to randomization for small trials [18]. Participants were recruited for each site and once they consented and cleared eligibility was added to the site list used for minimization matches. Pre-test scores, years of practice, practice area (urban/rural), and practice type (PT/OT) were used as the key predictors. At each site, the pool of participants was allocated minimizing difference by creating pair groupings based on professional training (PT/OT), matching area practice and then most similar pre-test scores, and, finally, by minimizing years of practice. When this process was complete, subjects at each site were informed of their assignment. Once allocation was complete no changes were made. These matches were performed by hand by an independent researcher.
A resource analysis of the use of the video function of electronic devices for home exercise instruction in rehabilitation
Published in Disability and Rehabilitation, 2021
Kellie B. Emmerson, Katherine E. Harding, Cynthia Fong, Nicholas F. Taylor
Since previous research demonstrated no difference in effectiveness [15,17], one issue that could influence the decision to provide exercise instructions using the video function of electronic devices is a difference in cost. The four approaches to economic evaluation include cost-benefit, cost-effectiveness, cost-utility and cost-minimization [18]. Cost minimization [18–20] assumes that the clinical outcomes are equal in both groups, and therefore the option with the lowest costs is preferred. The use of technology has the potential to save material resources (paper and printing) and time for clinicians if it can improve efficiency. However, it is also possible that time required for training or to address technical issues may outweigh any benefits. The aim of this study was to compare the health service costs when home exercise instructions were provided in paper-based mode versus when they were provided using the video function of electronic devices for patients receiving community rehabilitation.
“These Things Don’t Work.” Young People’s Views on Harm Minimization Strategies as a Proxy for Self-Harm: A Mixed Methods Approach
Published in Archives of Suicide Research, 2020
Ruth Wadman, Emma Nielsen, Linda O’Raw, Katherine Brown, A. Jess Williams, Kapil Sayal, Ellen Townsend
To date, very little research has explored how individuals who self-harm, or healthcare professionals, view harm minimization strategies. A structured interview study found relatively few young people (< 9%) reported using sensation or process proxies to resist the urge to self-harm (instead turning to others and receiving emotional support were generally reported to be helpful) (Klonsky & Glenn, 2008). Research exploring healthcare professionals’ views indicates that formulating plans around harm minimization strategies is seen as promoting empowerment, ensuring that the young person is an active participant in their own recovery (Tofthagen, Talseth, & Fagerström, 2014). However, it is also recognized that harm minimization strategies may be advantageous for some, but not all patients (Pembroke, 2006; Pengelly et al., 2008). Indeed, a recent qualitative study suggests that some mental health practitioners regard the use of harm minimizing strategies for self-harm as potentially useful (at least in inpatient settings) but others voiced concerns about their use, in terms of increased risk and escalating self-harm (James, Samuels, Moran, & Stewart, 2017). It is pertinent to note that: (1) this study considered harm-reduction and damage limitation strategies, as opposed to the sensation or process proxies for self-harm considered within the current study, and (2) the majority of staff who took part in the research had no direct experience of using harm minimization approaches.