Kerenza Hood

Mike Clarke

Paula R Williamson

Hywel Williams

Matthew Westmore

Erik von Elm

Liz Tremain

David Torgerson

Frank Sullivan

Lynne Restrup

Craig Ramsay

Adwoa Parker

Roberta Littleford

Jan Jansen

Shaun Treweek

Katie Gillies

Heidi Gardner

	Sandra Galvin

Adel El Feky

Declan Devane

Seonaidh Cotton

Clive Collett

Jacquie Christie

Marion Campbell

Matthias Briel

Peter Bower

Simon Bevan

https://doi.org/10.1186/s13063-019-3980-5

Figure 1

Figure 2

Trial Forge Guidance 2: How to decide if a further Study Within A Trial (SWAT) is needed

Trials

CC BY 4.0

The evidence base available to trialists to support trial process decisions– e.g. how best to recruit and retain participants, how to collect data or how to share the results with participants – is thin. One way to fill gaps in evidence is to run Studies Within A Trial, or SWATs. These are self-contained research studies embedded within a host trial that aim to evaluate or explore alternative ways of delivering or organising a particular trial process.
SWATs are increasingly being supported by funders and considered by trialists, especially in the UK and Ireland. At some point, increasing SWAT evidence will lead funders and trialists to ask : given the current body of evidence for a SWAT, do we need a further evaluation in a another host trial? A framework for answering such a question is needed to avoid SWATs themselves contributing to research waste.
This paper presents criteria on when enough evidence is available for SWATs that use randomised allocation to compare different interventions.

Recommendation: Accept
Form responses:
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* Level of interest: **An article of importance in its field**
* Quality of written English: **Acceptable**
* Quality of figures: **Not acceptable**
* Statistical review: **No, the manuscript does not need to be seen by a statistician**
* Declaration of competing interests: **I declare that I have no competing interests**

Comments to Author:
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Authors have greatly improved the clarity of the manuscript and I have no further concerns.

Form responses:
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* Quality of written English
Please indicate the quality of language in the manuscript:	Needs some language corrections before being published: **Quality of figures
All images and figures within the manuscript should be genuine i.e. without evidence of manipulation. No specific feature within an image may be enhanced, obscured, moved, removed, or introduced. If you have concerns about the veracity of the figures you should choose the first option below.	Acceptable**


Form responses:
---
* Level of interest: **An article of importance in its field
**
* Quality of written English: **Needs some language corrections before being published**
* Quality of figures: **Acceptable**
* Statistical review: **No, the manuscript does not need to be seen by a statistician**
* Declaration of competing interests: **I declare that I have no competing interests**

Comments to Author:
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Thank you for asking me to review this interesting paper on deciding whether to propose additional studies within a trial (SWAT's).

I think this is a useful addition to the literature. It is generally well written although it includes UK slang which I think could be edited (e.g "a bunch of outcomes").

My main comment is with the examples - I think one of the examples should be an illustration of when there is enough evidence to decide NOT to do another SWAT. At the moment both examples conclude that doing another SWAT is a reasonable option. (I note the authors briefly discuss this in the discussion but the paper would be stronger if they can come up with an "negative" example). Second context is a significant part of the decision making in the criteria suggested by the authors. I think the authors should if possible use real life examples or at least provide more information about the context of decision making in the examples. Lastly I think the authors should be far more explicit about the role of people with lived experience in the decision making criteria and examples.

General Medicine

Trial Forge Guidance 2: How to decide if a further Study Within A Trial (SWAT) is needed

Status:

Journal Publication

Version 1

Abstract

Figures

Supplementary Files

Status:

Journal Publication

Version 1