Evidence map›Paper›PMID 30305155›Full record

GuidelineTrials2018

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

William Sones, Steven A Julious, Joanne C Rothwell, Craig Robert Ramsay, Lisa V Hampson, Richard Emsley, Stephen J Walters, Catherine Hewitt, Martin Bland, Dean A Fergusson and 4 more

Erratum issuedAbstract readConsensus StatementPractice GuidelineSystematic Review
PubMed Full text at PMC Publisher
In one paragraph

Guideline in Trials, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Article
  2. DELTATrials · 2018
    Article
4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

14 authors.

William SonesCentre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Botnar Research Centre, Nuffield Orthopaedic Centre, Windmill Rd, Oxford, OX3 7LD, UK.
Steven A JuliousMedical Statistics Group, ScHARR, The University of Sheffield, Regent Court, 30 Regent Street, Sheffield, S1 4DA, UK.
Joanne C RothwellMedical Statistics Group, ScHARR, The University of Sheffield, Regent Court, 30 Regent Street, Sheffield, S1 4DA, UK.
Craig Robert RamsayHealth Services Research Unit, University of Aberdeen, Health Sciences Building, Foresterhill, Aberdeen, AB25 2ZD, UK.
Lisa V HampsonDepartment of Mathematics and Statistics, Lancaster University, Lancaster, LA1 4YF, UK.
Richard EmsleyDepartment of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, Denmark Hill, London, SE5 8AF, UK.
Stephen J WaltersMedical Statistics Group, ScHARR, The University of Sheffield, Regent Court, 30 Regent Street, Sheffield, S1 4DA, UK.
Catherine HewittDepartment of Health Sciences, Seebohm Rowntree Building, University of York, Heslington, York, YO10 5DD, UK.
Martin BlandDepartment of Health Sciences, Seebohm Rowntree Building, University of York, Heslington, York, YO10 5DD, UK.
Dean A FergussonClinical Epidemiology Program, Ottawa Hospital Research Institute, 501 Smyth Road, Box 201B, Ottawa, ON, K1H 8L6, Canada.
Jesse A BerlinJohnson & Johnson, One J&J Plaza, New Brunswick, NJ, 08933, USA.
Doug AltmanCentre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Botnar Research Centre, Nuffield Orthopaedic Centre, Windmill Rd, Oxford, OX3 7LD, UK.
Luke David ValeHealth Economics Group, Institute of Health and Society, Newcastle University, Newcastle upon Tyne, UK.
Jonathan Alistair CookCentre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Botnar Research Centre, Nuffield Orthopaedic Centre, Windmill Rd, Oxford, OX3 7LD, UK. jonathan.cook@ndorms.ox.ac.uk.ORCID http://orcid.org/0000-0002-4156-6989

Funding

Chief Scientist Office HSRU1Medical Research Council MC_PC_16101
6 · The paper itself

Abstract

backgroundA 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 DELTA

methodsThe DELTA

resultsThe 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 DELTA

Indexed as

Clinical Trial Protocols as TopicNumbers Needed To TreatConsensusData Interpretation, StatisticalDelphi TechniqueHumansRandomized Controlled Trials as TopicTreatment OutcomeClinically important differenceDelphiEffect sizeGuidanceRandomised trialSample sizeTarget difference

Identifiers

PMID30305155
PMCPMC6180499

What OpenQuestion holds

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LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.