Summary of review finding	Studies contributing to the review finding	Methodological limitations	Coherence	Relevance		Adequacy	CERQual assessment of confidence in the evidence	Explanation of CERQual assessment
Finding 1: Trial information delivered verbally during face‐to‐face communication can be less confusing than written trial information	Barnes 2012, Moynihan 2012, Bleidorn 2015, Oud‐Rengerink 2015, Attwood 2016, Dellson 2018	Minor concerns based on the assessment of four studies with no, and two studies with minor methodological limitations	No or very minor concerns		Minor concerns regarding relevance as studies had moderate geographical spread Included a range of medical/surgical, oncology, mental health, pregnancy and childbirth, and health promotion trials. Participants included both acceptors and decliners.	No or very minor concerns	High Confidence	No or very minor concerns regarding coherence, minor concerns regarding relevance and methodological limitations, and minor concerns regarding adequacy
Finding 2: Written trial information may be beneficial as an adjunct to verbal information and facilitates time and space for reflection without the added influence of recruiters’ presence	Hughes‐Morley 2016, Jackson 2010, Sawyer 2017, Smyth 2011, Bleidorn 2015, Blodt 2016, de Lacey 2017	Minor concerns based on the assessment of five studies with no, and two studies with minor methodological limitations	No or very minor concerns		Minor concerns regarding relevance as studies had moderate geographical spread Included a range of medical/surgical, oncology, mental health and pregnancy and childbirth. Participants included both acceptors and decliners.	No or very minor concerns	High Confidence	No or very minor concerns regarding coherence, minor concerns regarding relevance and methodological limitations, and minor concerns regarding adequacy
Finding 3: The person delivering trial information should have good communication skills, be approachable, trustworthy, person‐centred and knowledgeable with a good ability to address potential participants’ queries. Consideration needs to be given to whether a clinician or a researcher is the most appropriate person to provide the trial information	Abhyankar 2016, Chang 2004, Costenbader 2007, Harrop 2016a, Madsen 2007a, Madsen 2007b, Jackson 2010, Moynihan 2012, Smyth 2011, Habersack 2013, Oud‐Rengerink 2015, Tarimo 2010Bleidorn 2015, Ballantyne 2017, Sawyer 2017	Minor concerns based on the assessment of eleven studies with no, and three studies with minor and one study with moderate methodological limitations	No or very minor concerns		Moderate concerns regarding relevance as studies had moderate geographical spread Included a range of medical/surgical, oncology and pregnancy and childbirth. Participants included both acceptors and decliners.	No or very minor concerns	High Confidence	No or very minor concerns regarding coherence, moderate concerns regarding relevance and methodological limitations, and minor concerns regarding adequacy
Finding 4: Potential participants value trial information that is robust yet concise, free of medical jargon, clearly identifies options, time commitment, randomisation process, treatment equivalence, intervention details, potential benefits and side effects. This could be made available in hard or soft copy, or both before a decision on participation is expected	Jackson 2010, Hughes‐Morley 2016, Sawyer 2017, Taylor 2007, Habersack 2013, Oud‐Rengerink 2015, Canvin 2006, Costenbader 2007, Madsen 2007b, McCann 2010, Smyth 2011, Abhyankar 2016, Bidad 2016, Harrop 2016a, Ballantyne 2017, Dellson 2018, Attwood 2016, Blodt 2016, Moynihan 2012.	Minor concerns based on the assessment of fifteen studies with no, and three studies with minor and one study with moderate methodological limitations	No or very minor concerns		Minor concerns regarding relevance as studies had moderate geographical spread Included a range of medical/surgical, oncology, mental health, pregnancy and childbirth, and health promotion trials. Participants included both acceptors and decliners.	No or very minor concerns	High Confidence	No or very minor concerns regarding coherence, minor concerns regarding relevance and methodological limitations, and minor concerns regarding adequacy
Finding 5: The timing of trial information is important as the potential participant needs to be able to consider the trial information without confusing it with their diagnosis and standard treatment	Abhyankar 2016Madsen 2007b, Moynihan 2012, Smyth 2011, Habersack 2013, Hughes‐Morley 2016, Sawyer 2017, Dellson 2018	Minor concerns based on the assessment of six studies with no, and two studies with minor methodological limitations	No or very minor concerns		Moderate concerns regarding relevance as studies had moderate geographical spread Included a range of, oncology, mental health and pregnancy and childbirth trials. Participants included both acceptors and decliners.	No or very minor concerns	High Confidence	No or very minor concerns regarding coherence, moderate concerns regarding relevance and methodological limitations, and minor concerns regarding adequacy