Home > Research > Publications & Outputs > Choosing the target difference and undertaking ...

Research

Links

Text available via DOI:

Keywords

View graph of relations

Choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial - The development of the DELTA2 guidance

Research output: Contribution to Journal/Magazine › Journal article › peer-review

Published

Standard

Choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial - The development of the DELTA2 guidance. / Sones, W.; Julious, S.A.; Rothwell, J.C. et al.
In: Trials, Vol. 19, No. 1, 542, 10.10.2018.

Research output: Contribution to Journal/Magazine › Journal article › peer-review

Harvard

Sones, W, Julious, SA, Rothwell, JC, Ramsay, CR, Hampson, LV, Emsley, R, Walters, SJ, Hewitt, C, Bland, M, Fergusson, DA, Berlin, JA, Altman, D, Vale, LD & Cook, JA 2018, 'Choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial - The development of the DELTA2 guidance', Trials, vol. 19, no. 1, 542. https://doi.org/10.1186/s13063-018-2887-x

APA

Sones, W., Julious, S. A., Rothwell, J. C., Ramsay, C. R., Hampson, L. V., Emsley, R., Walters, S. J., Hewitt, C., Bland, M., Fergusson, D. A., Berlin, J. A., Altman, D., Vale, L. D., & Cook, J. A. (2018). Choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial - The development of the DELTA2 guidance. Trials, 19(1), Article 542. https://doi.org/10.1186/s13063-018-2887-x

Vancouver

Sones W, Julious SA, Rothwell JC, Ramsay CR, Hampson LV, Emsley R et al. Choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial - The development of the DELTA2 guidance. Trials. 2018 Oct 10;19(1):542. doi: 10.1186/s13063-018-2887-x

Author

Sones, W. ; Julious, S.A. ; Rothwell, J.C. et al. / Choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial - The development of the DELTA2 guidance. In: Trials. 2018 ; Vol. 19, No. 1.

Bibtex

@article{74b69077b76f4daa9ad7ef345170e2a6,
title = "Choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial - The development of the DELTA2 guidance",
abstract = "Background: A key step in the design of a randomised controlled trial is the estimation of the number of participants needed. The most common approach is to specify a target difference in the primary outcome between the randomised groups and then estimate the corresponding sample size. The sample size is chosen to provide reassurance that the trial will have high statistical power to detect the target difference at the planned statistical significance level. Alternative approaches are also available, though most still require specification of a target difference. The sample size has many implications for the conduct of the study, as well as incurring scientific and ethical aspects. Despite the critical role of the target difference for the primary outcome in the design of a randomised controlled trial (RCT), the manner in which it is determined has received little attention. This article reports the development of the DELTA2 guidance on the specification and reporting of the target difference for the primary outcome in a sample size calculation for a RCT. Methods: The DELTA2 (Difference ELicitation in TriAls) project has five components comprising systematic literature reviews of recent methodological developments (stage 1) and existing funder guidance (stage 2), a Delphi study (stage 3), a 2-day consensus meeting bringing together researchers, funders and patient representatives (stage 4), and the preparation and dissemination of a guidance document (stage 5). Results: The project started in April 2016. The literature search identified 28 articles of methodological developments relevant to a method for specifying a target difference. A Delphi study involving 69 participants, along with a 2-day consensus meeting were conducted. In addition, further engagement sessions were held at two international conferences. The main guidance text was finalised on April 18, 2018, after revision informed by feedback gathered from stages 2 and 3 and from funder representatives. Discussion: The DELTA2 Delphi study identified a number of areas (such as practical recommendations and examples, greater coverage of different trial designs and statistical approaches) of particular interest amongst stakeholders which new guidance was desired to meet. New relevant references were identified by the review. Such findings influenced the scope, drafting and revision of the guidance. While not all suggestions could be accommodated, it is hoped that the process has led to a more useful and practical document. {\textcopyright} 2018 The Author(s).",
keywords = "Clinically important difference, Delphi, Effect size, Guidance, Randomised trial, Sample size, Target difference, adult, article, attention, calculation, consensus, Delphi study, effect size, ethics, female, human, male, outcome assessment, randomized controlled trial (topic), sample size, scientist, systematic review",
author = "W. Sones and S.A. Julious and J.C. Rothwell and C.R. Ramsay and L.V. Hampson and R. Emsley and S.J. Walters and C. Hewitt and M. Bland and D.A. Fergusson and J.A. Berlin and D. Altman and L.D. Vale and J.A. Cook",
year = "2018",
month = oct,
day = "10",
doi = "10.1186/s13063-018-2887-x",
language = "English",
volume = "19",
journal = "Trials",
issn = "1745-6215",
publisher = "BIOMED CENTRAL LTD",
number = "1",

}

RIS

TY - JOUR

T1 - Choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial - The development of the DELTA2 guidance

AU - Sones, W.

AU - Julious, S.A.

AU - Rothwell, J.C.

AU - Ramsay, C.R.

AU - Hampson, L.V.

AU - Emsley, R.

AU - Walters, S.J.

AU - Hewitt, C.

AU - Bland, M.

AU - Fergusson, D.A.

AU - Berlin, J.A.

AU - Altman, D.

AU - Vale, L.D.

AU - Cook, J.A.

PY - 2018/10/10

Y1 - 2018/10/10

N2 - Background: A key step in the design of a randomised controlled trial is the estimation of the number of participants needed. The most common approach is to specify a target difference in the primary outcome between the randomised groups and then estimate the corresponding sample size. The sample size is chosen to provide reassurance that the trial will have high statistical power to detect the target difference at the planned statistical significance level. Alternative approaches are also available, though most still require specification of a target difference. The sample size has many implications for the conduct of the study, as well as incurring scientific and ethical aspects. Despite the critical role of the target difference for the primary outcome in the design of a randomised controlled trial (RCT), the manner in which it is determined has received little attention. This article reports the development of the DELTA2 guidance on the specification and reporting of the target difference for the primary outcome in a sample size calculation for a RCT. Methods: The DELTA2 (Difference ELicitation in TriAls) project has five components comprising systematic literature reviews of recent methodological developments (stage 1) and existing funder guidance (stage 2), a Delphi study (stage 3), a 2-day consensus meeting bringing together researchers, funders and patient representatives (stage 4), and the preparation and dissemination of a guidance document (stage 5). Results: The project started in April 2016. The literature search identified 28 articles of methodological developments relevant to a method for specifying a target difference. A Delphi study involving 69 participants, along with a 2-day consensus meeting were conducted. In addition, further engagement sessions were held at two international conferences. The main guidance text was finalised on April 18, 2018, after revision informed by feedback gathered from stages 2 and 3 and from funder representatives. Discussion: The DELTA2 Delphi study identified a number of areas (such as practical recommendations and examples, greater coverage of different trial designs and statistical approaches) of particular interest amongst stakeholders which new guidance was desired to meet. New relevant references were identified by the review. Such findings influenced the scope, drafting and revision of the guidance. While not all suggestions could be accommodated, it is hoped that the process has led to a more useful and practical document. © 2018 The Author(s).

AB - Background: A key step in the design of a randomised controlled trial is the estimation of the number of participants needed. The most common approach is to specify a target difference in the primary outcome between the randomised groups and then estimate the corresponding sample size. The sample size is chosen to provide reassurance that the trial will have high statistical power to detect the target difference at the planned statistical significance level. Alternative approaches are also available, though most still require specification of a target difference. The sample size has many implications for the conduct of the study, as well as incurring scientific and ethical aspects. Despite the critical role of the target difference for the primary outcome in the design of a randomised controlled trial (RCT), the manner in which it is determined has received little attention. This article reports the development of the DELTA2 guidance on the specification and reporting of the target difference for the primary outcome in a sample size calculation for a RCT. Methods: The DELTA2 (Difference ELicitation in TriAls) project has five components comprising systematic literature reviews of recent methodological developments (stage 1) and existing funder guidance (stage 2), a Delphi study (stage 3), a 2-day consensus meeting bringing together researchers, funders and patient representatives (stage 4), and the preparation and dissemination of a guidance document (stage 5). Results: The project started in April 2016. The literature search identified 28 articles of methodological developments relevant to a method for specifying a target difference. A Delphi study involving 69 participants, along with a 2-day consensus meeting were conducted. In addition, further engagement sessions were held at two international conferences. The main guidance text was finalised on April 18, 2018, after revision informed by feedback gathered from stages 2 and 3 and from funder representatives. Discussion: The DELTA2 Delphi study identified a number of areas (such as practical recommendations and examples, greater coverage of different trial designs and statistical approaches) of particular interest amongst stakeholders which new guidance was desired to meet. New relevant references were identified by the review. Such findings influenced the scope, drafting and revision of the guidance. While not all suggestions could be accommodated, it is hoped that the process has led to a more useful and practical document. © 2018 The Author(s).

KW - Clinically important difference

KW - Delphi

KW - Effect size

KW - Guidance

KW - Randomised trial

KW - Sample size

KW - Target difference

KW - adult

KW - article

KW - attention

KW - calculation

KW - consensus

KW - Delphi study

KW - effect size

KW - ethics

KW - female

KW - human

KW - male

KW - outcome assessment

KW - randomized controlled trial (topic)

KW - sample size

KW - scientist

KW - systematic review

U2 - 10.1186/s13063-018-2887-x

DO - 10.1186/s13063-018-2887-x

M3 - Journal article

VL - 19

JO - Trials

JF - Trials

SN - 1745-6215

IS - 1

M1 - 542

ER -