Why “underpowered” trials are not necessarily unethical

Edwards, Sarah; Lilford, Richard; Braunholtz, David; Jackson, J. Edward

doi:10.1016/s0140-6736(97)02290-3

Cited by 90 publications

(68 citation statements)

References 24 publications

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“…Thus, researchers are strongly recommended to ensure a sufficient power if a treatment is to be compared to an established treatment, or they should at least include an additional waiting list or TAU condition in order to be able to demonstrate efficacy. However, the existing underpowered RCTs are not necessarily useless or unethical [149,150]. If they are included in a meta-analysis, the statistical power will increase beyond that of the individual study, with the power depending not only on the number of studies and patients but also on the degree of heterogeneity between studies [151].…”

Section: Discussionmentioning

confidence: 99%

The Empirical Status of Psychodynamic Psychotherapy - An Update: Bambi's Alive and Kicking

Leichsenring

Leweke

Klein

et al. 2015

Psychother Psychosom

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Background: The Task Force on Promotion and Dissemination of Psychological Procedures proposed rigorous criteria to define empirically supported psychotherapies. According to these criteria, 2 randomized controlled trials (RCTs) showing efficacy are required for a treatment to be designated as ‘efficacious' and 1 RCT for a designation as ‘possibly efficacious'. Applying these criteria modified by Chambless and Hollon, this article presents an update on the evidence for psychodynamic therapy (PDT) in specific mental disorders. Methods: A systematic search was performed using the criteria by Chambless and Hollon for study selection, as follows: (1) RCT of PDT in adults, (2) use of reliable and valid measures for diagnosis and outcome, (3) use of treatment manuals or manual-like guidelines, (4) adult population treated for specific problems and (5) PDT superior to no treatment, placebo or alternative treatment or equivalent to an established treatment. Results: A total of 39 RCTs were included. Following Chambless and Hollon, PDT can presently be designated as efficacious in major depressive disorder (MDD), social anxiety disorder, borderline and heterogeneous personality disorders, somatoform pain disorder, and anorexia nervosa. For MDD, this also applies to the combination with pharmacotherapy. PDT can be considered as possibly efficacious in dysthymia, complicated grief, panic disorder, generalized anxiety disorder, and substance abuse/dependence. Evidence is lacking for obsessive-compulsive, posttraumatic stress, bipolar and schizophrenia spectrum disorder(s). Conclusions: Evidence has emerged that PDT is efficacious or possibly efficacious in a wide range of common mental disorders. Further research is required for those disorders for which sufficient evidence does not yet exist.

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Section: Discussionmentioning

confidence: 99%

The Empirical Status of Psychodynamic Psychotherapy - An Update: Bambi's Alive and Kicking

Leichsenring

Leweke

Klein

et al. 2015

Psychother Psychosom

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show abstract

“…Clinical trialists and 'statisticians have for a long time argued that this [approach] is inappropriate and that trials should be used to estimate treatment effects and not to test hypotheses' (p. 806). 5 This might go against everything some have been taught. However, the push away from P-values and hypothesis testing is not new, and journals are increasingly trying to encourage researchers and readers to focus on estimates of treatment effects 6 (the uncertainty of those estimates can be quantified with confidence intervals).…”

mentioning

confidence: 99%

Statistical power calculations reflect our love affair with P-values and hypothesis testing: time for a fundamental change

Harvey

2014

Spinal Cord

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“…It seems likely that either one or more of the findings represent type I error or, less parsimoniously, that there are two or more susceptibility loci for bipolar disorder on chromosome 18. Although it is very important to interpret negative studies within the context of their power to detect an effect, it is vital that both positive and negative studies are made available to the research community to reduce the effect of publication bias on the interpretation of the world literature [Edwards et al, 1997]. Ultimately, it is almost certain to be necessary to undertake combined analysis of multiple large data sets to confirm or refute the existence of a bipolar susceptibility gene in this region.…”

Section: Discussionmentioning

confidence: 99%

Linkage studies of bipolar disorder with chromosome 18 markers

et al. 1999

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Evidence consistent with the existence of genetic linkage between bipolar disorder and three regions on chromosome 18, the pericentromeric region, 18q21, and 18q22-q23 have been reported. Some analyses indicated greater evidence for linkage in pedigrees in which paternal transmission of disease occurs. We have undertaken linkage analyses using 12 highly polymorphic markers spanning these three regions of interest in a sample of 48 U.K. bipolar pedigrees. The sample comprises predominantly nuclear families and includes 118 subjects with Diagnostic and Statistical Manual of Mental Disorders (DSM IV) bipolar I disorder and 147 subjects with broadly defined phenotype. Our data do not provide support for linkage using either parametric or nonparametric analyses. Evidence for linkage was not significantly increased by analyses that allowed for heterogeneity nor by analysing the subset of pedigrees consistent with paternal transmission.

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Why “underpowered” trials are not necessarily unethical

Cited by 90 publications

References 24 publications

The Empirical Status of Psychodynamic Psychotherapy - An Update: Bambi's Alive and Kicking

The Empirical Status of Psychodynamic Psychotherapy - An Update: Bambi's Alive and Kicking

Statistical power calculations reflect our love affair with P-values and hypothesis testing: time for a fundamental change

Linkage studies of bipolar disorder with chromosome 18 markers

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