Table 2. Developed country consent studies.

Authors	Country	Sample	Type of clinical research	Method of evaluation
Ellis et al, 2010¹⁸	USA	171 M and F	Malaria vaccine phase I trial	Questionnaire administered after IC document reviewed but before consent
Ravina et al, 2010³⁶	USA	149 M and F	Phase II Parkinson's trial	Self-administered questionnaire at final clinical trial visit
Bergenmar et al, 2008³⁷	Sweden	282 M and F	Phase II and phase III oncology trials	Mail surveys sent within 3 days–2 weeks of consent
Knifed et al, 2008³⁸	Canada	21 M and F	Neuro-oncology trial	Interviews within 1 month of IC
Agrawal et al, 2006³⁹	USA	163 M and F	Phase I oncology trials	Interview immediately after consent
Franck et al, 2007⁴⁰	UK	109 Parents	25 Different paediatric studies	Questionnaire taken immediately after and 3 months after consent
Marshall et al, 2006¹⁹	USA	348 M and F	Genetic studies of hypertension	Interviews long and variably after consent
Gammelgaard et al, 2004⁴¹	Denmark	103 M and F	Acute myocardial infarction trials	Mail survey sent to participants in the study 3 weeks after IC
Kodish et al, 2004⁴²	USA	137 Parents	Paediatric leukaemia trial	Parent pairs interviewed within 48 h of consent
Lynöe et al, 2004⁴³	Sweden	44 M and F	Chronic haemodialysis trials	Mail survey about 1 week after disclosure of information
Criscione et al, 2003⁴⁴	USA	30 M and F	Rheumatoid arthritis trial	Questionnaire 1–4 weeks after consent
Kupst et al, 2003⁴⁵	USA	20 Parents	Paediatric oncology trials	Interviews 1 month after IC
Pope et al, 2003⁴⁶	Canada	190 M and F	Cardiology, ophthalmology and rheumatology trials	Mail survey 2–5 months after consent
Schats et al, 2003⁴⁷	The Netherlands	37 M and F	Subarachnoid haemorrhage emergency management trials	Interviews 7–31 months after IC (median of 20 months)
Simon et al, 2003⁴⁸	USA	Majority English speakers: 60 parents	Paediatric oncology trials	Parents interviewed 48 h after consent
		Minority English Speakers: 27 parents
		Minority non-English speakers: 21 parents
Joffe et al, 2001⁴⁹	USA	207 M and F	Oncology trials, phase I, II and III	Mail survey 1–2 weeks after consent
Daugherty et al, 2000⁵⁰	USA	144 M and F	Phase I oncology trials	Interviews within 1 week of first administration of investigational treatment
Hietanen et al, 2000⁵¹	Finland	261 F	Oncology trial of tamoxifen	Mail survey 5–17 months after consent
Montgomery et al, 1998⁵²	UK	158 M and F	3 In-house and 3 multi-centre anaesthesia trials	Mail survey up to 24 months after consent
Van Stuijvenberg et al, 1998⁵³	The Netherlands	181 Parents	Paediatric trial of ibuprofen for febrile convulsions	Mail survey up to 2–3 years after consent
ACHRE, 1996⁵⁴	USA	570 M and F	Oncology and cardiology trials	Brief interviews followed by in-depth interviews
Harrison et al, 1995⁵⁵	USA	71 M and F	HIV vaccine trial	Self-administered questionnaire after disclosure and before consent
Harth et al, 1995⁵⁶	Australia	62 Parents	Paediatric trial of oral asthma drug	Self-administered questionnaire 6–9 months after entered trial
Estey et al, 1994⁵⁷	Canada	29 M and F	Not specified	Interviews 1–6 weeks after consent
Miller et al, 1994⁵⁸	USA	168 M and F	Trial of analgesic drugs	Interviews 30–90 days after entered trial
Lynöe et al, 1991⁵⁹	Sweden	43 F	Gynaecology trial of antiphlogistic drugs for fallopian tube inflammation	Mail survey 18 months after study
Benson et al, 1985⁶⁰	USA	Depression study: 24 M and F	Antidepressant trial and antipsychotic trial	Interviews immediately following IC
		Schizophrenia study: 24 M
Penman et al, 1984⁶¹	USA	144 M and F	Oncology trials, phase II and III	Interviews 1–3 weeks after consent
Riecken et al, 1982⁶²	USA	112 M^*	50 Different trials	Interviews within 10 weeks of consent
Howard et al, 1981⁶³	USA	64 M and F	Cardiology trial of β-blockers (BHAT) for acute myocardial infarction	Interviews 2 weeks–15 months after consent
Bergler et al, 1980⁶⁴	USA	39 M	Hypertension trial of hydrochlorothiazide versus propranolol	Interviews and quizzes just after consent; repeated 3 months later

The trial involved 156 participants, but only 112 indicated that they were aware that they were participating in a trial, and therefore only 112 were asked questions about voluntariness. ACHRE, Advisory Committee on Human Radiation Experiments; F, female; IC, informed consent; M, male.