Background Informed consent is a requirement for all research. It is not, however, clear how much information is sufficient to make an informed decision about participation in research. Information on an online questionnaire about childhood development was provided through an unfolding electronic participant sheet in three levels of information. Methods 552 participants, who completed the web-based survey, accessed and spent time reading the participant information sheet (PIS) between July 2008 and November 2009. The information behaviour of the participants was investigated. (...) The first level contained less information than might be found on a standard PIS, the second level corresponded to a standard PIS, and the third contained more information than on a standard PIS. The actual time spent on reading the information provided in three incremental levels and the participants' evaluation of the information were calculated. Results 77% of the participants chose to access the first level of information, whereas 12% accessed the first two levels, 6% accessed all three levels of information and 23% participated without accessing information. The most accessed levels of information were those that corresponded to the average reading times. Conclusion The brief information provided in the first level was sufficient for participants to make informed decisions, while a sizeable minority of the participants chose not to access any information at all. This study adds to the debate about how much information is required to make a decision about participation in research and the results may help inform the future development of information sheets by providing data on participants' actual needs when deciding about questionnaire surveys. (shrink)

Background Participants' understanding of clinical trials is important in informed consent. However, little is known about what information participants really want to know. Aims To demonstrate the existence of a discrepancy between participants' understanding and their desire to know. Methods The participants in clinical trials at Seoul National University Hospital were surveyed. The survey consisted of 11 statements based on the essential elements of informed consent. The participants gave two responses to each statement on a five-point Likert scale to rate (...) their subjective understanding and desire to know, respectively. Information discrepancy was defined as the difference between these two ratings: if understanding exceeded desire to know for a particular item, it was defined as ‘over-informed’; if desire to know exceeded understanding for a particular item, it was defined as ‘under-informed’. Results Participants reported good understanding of ‘voluntariness’, ‘duration’, ‘study involves research’ and poor understanding of ‘confidentiality’, ‘compensation’, ‘benefits’, ‘procedures’ and ‘risks or discomforts’. For ‘risks or discomforts’, ‘who to contact’, ‘voluntariness’, ‘duration’ and ‘procedures’, participants reported high desire to know compared with ‘confidentiality’, ‘purpose’, ‘study involves research’ and ‘benefits’. The elements ‘study involves research’, ‘voluntariness’, ‘duration’, ‘purpose’ and ‘who to contact’ were over-informed, while ‘compensation’, ‘risks or discomforts’, ‘procedures’, ‘confidentiality’ and ‘benefits’ were under-informed. Participants over 50 years of age, those without a college education and those whose participation was less voluntary were relatively less informed about the clinical trials. Conclusions An information discrepancy was observed between the participants' understanding and their desire to know. By putting more emphasis on under-informed elements, the quality of informed consent could be improved. (shrink)