Table 1.

Capacities of children according to studies

Author	Year	Number of subjects	Age	Question posed to children (example)	Conclusion
Weithorn L, Campbell SB	1982	96	9-21	“What happens if a person is taking insulin and misses one injection?”	“Children as young as 9 appear able to participate meaningfully in personal health-care decision making”.
Abramovitch R et al.	1991	163	5-21	“Should you be in a study if you didn’t like it and your mother did?”	“If the instructions are given clearly and the study is not excessively complex, most children as young as 5 are capable of understanding what they will be doing and therefore have the capacity to give their assent or dissent to the research”.
Susman EJ et al.	1992	44	7-20	“What are the side effects of taking your treatment?”	“Although we found no age differences, developmental differences do exist among children, adolescents, and adults […]. Adolescents and young adults were no better than children in comprehending abstract concepts”.
Ondrusek N et al.	1998	18	5-18	“What good things might happen to other people because you are in this study?”	“In subjects younger than 9 years of age, understanding of most aspects of the study was found to be poor to non-existent”.
Miller S	2000	6	7-12	“The children were […] asked to talk about their likes and dislikes”.	Researchers should not “underestimate the awareness and maturity that some children possess when addressing issues of concern to themselves”.
Geller G et al.	2003	37 dyads of parents and children	10-17 with parents	No information regarding questions posed.	“Most children wanted or expected some degree of parental input, but still thought the final decision should be theirs”.
Burke TM et al.	2005	251	6-13	“Can you think of any good things about being in the study?”	“By creating age appropriate modules of information, children as young as six years can understand potentially difficult and complex concepts […] associated with participation in biomedical research”.