DELTA<sup>2</sup> guidance on choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial

Cook, Jonathan; Julious, Steven A.; Sones, William; Hampson, Lisa V.; Hewitt, Catherine; Berlin, Jesse A.; Ashby, Deborah; Emsley, Richard; Fergusson, Dean; Walters, Stephen J.; Wilson, Ed; MacLennan, Graeme; Stallard, Nigel; Rothwell, Joanne; Bland, Martin; Brown, Louise; Ramsay, Craig; Cook, Andrew; Armstrong, David; Altman, Doug; Vale, Luke

doi:10.1136/bmj.k3750

Cited by 124 publications

(142 citation statements)

References 25 publications

(27 reference statements)

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“…Nevertheless, such knowledge can be difficult to derive. We refer readers to the DELTA and DELTA2 publications for a full treatment of this topic, including all the approaches for arriving at a MCID (Cook et al, 2014(Cook et al, , 2018.…”

Section: Measurementsmentioning

confidence: 99%

PRESENT 2020: Text Expanding on the Checklist for Proper Reporting of Evidence in Sport and Exercise Nutrition Trials

Betts

Gonzalez

Burke³

et al. 2020

International Journal of Sport Nutrition and Exercise Metabolism

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Section: Measurementsmentioning

confidence: 99%

PRESENT 2020: Text Expanding on the Checklist for Proper Reporting of Evidence in Sport and Exercise Nutrition Trials

Betts

Gonzalez

Burke³

et al. 2020

International Journal of Sport Nutrition and Exercise Metabolism

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“…Following preliminary planning, we followed the DELTA 2 guideline to estimate the minimum sample size for the study [27]. Frederick and VanderWeele's metaanalysis [7] was used to specify the important and realistic target difference for the primary outcome, with an estimate of its uncertainty.…”

Section: Sample Sizementioning

confidence: 99%

Protocol for a multi-centre, definitive randomised controlled trial of the effectiveness of Individual Placement and Support for employment support among people with alcohol and drug dependence

Marsden

Anders

Clark

et al. 2020

Trials

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Background: Unemployment is highly prevalent in populations with alcohol and drug dependence and the employment support offered in addiction-treatment programmes is ineffective. Individual Placement and Support (IPS) is an evidencebased intervention for competitive employment. IPS has been extensively studied in severe mental illness and physical disabilities, but there have been no formal randomised controlled trials (RCTs) in alcohol and drug dependence. The Individual Placement and Support for Alcohol and Drug Dependence (IPS-AD) study should determine whether IPS for patients with alcohol use disorder (AUD), opioid use disorder (OUD) and other drug use disorder is effective. Design/methods: The IPS-AD study is a seven-site, pragmatic, two-arm, parallel-group, superiority RCT. IPS-AD includes a realist process evaluation. Eligible patients (adult, unemployed or economically inactive for at least 6 months and wishing to obtain open job market employment and enrolled in ongoing community treatment-as-usual (TAU; the control condition) in England for AUD, OUD and other drug use disorders) will be randomised (1:1) to receive TAU and any standard employment support, or TAU plus IPS (the experimental condition) for 9 months with up to 4 months of in-work support. The primary outcome measure will be competitive employment status (at least 1 day (7 h)) during an 18-month follow-up, determined by patient-level, trial-data-linkage with national tax and state benefit databases. From meta-analysis, an 18% target difference on this measure of vocational effectiveness (for the experimental intervention) and a two-sided 5% level of statistical significance, will require a minimum target sample of 832 participants to achieve 90% power for a pre-registered, mixed-effects, multi-variable logistic regression model. A maximum-likelihood multiple-imputation approach will manage missing outcome data. IPS-AD has six vocational secondary outcome measures during the 18-month follow-up: (1) total time in competitive employment (and corresponding National Insurance contributions and tax paid); (2) time from randomisation to first competitive employment; (3) number of competitive job appointments; (4) job tenure (length of longest held competitive employment); (5) sustained employment (tenure in a single appointment for at least 13 weeks); and (6) job search self-efficacy. A primary cost-benefit analysis and a secondary cost-effectiveness analysis will be done using the primary outcome and secondary vocational outcomes, respectively and will include addiction treatment and social and health outcomes and their associated reference costs. The process evaluation will address IPS implementation and delivery.

show abstract

“…Following preliminary planning, we followed the DELTA 2 guideline to estimate the minimum sample size for the study [27]. Frederick and VanderWeele's meta-analysis [7] was used to specify the important and realistic target difference for the primary outcome, with an estimate of its uncertainty.…”

Section: Sample Sizementioning

confidence: 99%

Protocol for a multi-centre, definitive randomised controlled trial of the effectiveness of Individual Placement and Support for employment support among people with alcohol and drug dependence

Marsden

Anders

Clark

et al. 2020

Preprint

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BACKGROUND : Unemployment is highly prevalent among populations with alcohol and drug dependence and employment support offered in addiction treatment programmes is ineffective. Individual Placement and Support (IPS) is an evidence-based intervention for competitive employment. IPS has been extensively studied in severe mental illness and physical disabilities, but there have been no formal randomised controlled trials in alcohol and drug dependence. The Individual Placement and Support for Alcohol and Drug Dependence (IPS-AD) study will determine whether IPS for patients with alcohol use disorder (AUD), opioid use disorder (OUD) and other drug use disorder is effective. DESIGN/METHODS: The IPS-AD study is a seven-site, pragmatic, two-arm, parallel group, superiority, randomised controlled trial. IPS-AD includes a realist process evaluation. Eligible patients (adult, unemployed or economically inactive for at least 6 months and wishing to obtain open job market employment and enrolled in ongoing community treatment-as-usual [TAU; the control condition] in England for AUD, OUD and other drug use disorders) will be randomised (1:1) to receive TAU and any standard employment support, or TAU plus IPS (the experimental condition) for nine months with up to four months of in-work support. The primary outcome measure will be competitive employment status (at least one day [7 hours]) during an 18-month follow-up, determined by patient-level, trial data-linkage with national tax and state benefit databases. From meta-analysis, an 18% target difference on this measure of vocational effectiveness (for the experimental intervention) and a two-sided 5% level of statistical significance, will require a minimum target sample of 832 participants to achieve 90% power for a pre-registered, mixed-effects, multi-variable logistic regression model. A maximum-likelihood multiple imputation approach will manage missing outcome data. IPS-AD has six vocational secondary outcome measures during the 18-month follow-up: (1) total time in competitive employment (and corresponding National Insurance contributions and tax paid); (2) time from randomisation to first competitive employment; (3) number of competitive job appointments; (4) job tenure (length of longest held competitive employment); (5) sustained employment (tenure in a single appointment for at least 13 weeks); and (6) job search self-efficacy. A primary cost-benefit analysis and a secondary cost-effectiveness analysis will be done using the primary outcome and secondary vocational outcomes, respectively and will include addiction treatment and social and health outcomes and their associated reference costs. The process evaluation will address IPS implementation and delivery. DISCUSSION : The IPS-AD study is the first large-scale, multi-site, definitive, superiority, RCT of IPS for people with alcohol and drug dependence. Findings from the study will have substantial implications for service delivery. TRIAL REGISTRATION : ISRCTN Registry, ISRCTN24159790. Registered on 1 February 2018. KEYWORDS : Individual Placement and Support, alcohol, opioids, drugs, dependence.

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DELTA² guidance on choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial

Cited by 124 publications

References 25 publications

PRESENT 2020: Text Expanding on the Checklist for Proper Reporting of Evidence in Sport and Exercise Nutrition Trials

PRESENT 2020: Text Expanding on the Checklist for Proper Reporting of Evidence in Sport and Exercise Nutrition Trials

Protocol for a multi-centre, definitive randomised controlled trial of the effectiveness of Individual Placement and Support for employment support among people with alcohol and drug dependence

Protocol for a multi-centre, definitive randomised controlled trial of the effectiveness of Individual Placement and Support for employment support among people with alcohol and drug dependence

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DELTA2 guidance on choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial

Cited by 124 publications

References 25 publications

PRESENT 2020: Text Expanding on the Checklist for Proper Reporting of Evidence in Sport and Exercise Nutrition Trials

PRESENT 2020: Text Expanding on the Checklist for Proper Reporting of Evidence in Sport and Exercise Nutrition Trials

Protocol for a multi-centre, definitive randomised controlled trial of the effectiveness of Individual Placement and Support for employment support among people with alcohol and drug dependence

Protocol for a multi-centre, definitive randomised controlled trial of the effectiveness of Individual Placement and Support for employment support among people with alcohol and drug dependence

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Product

Resources

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DELTA² guidance on choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial