Research with Children

Who is a "Child" for Research Purposes?

The federal regulations on human subjects research define “children” as follows:

“Children” are persons who have not attained the legal age for consent to treatments or procedures involved in the research, under the applicable law of the jurisdiction in which the research will be conducted (45 CFR 46.402(a)).

In the United States, the legal age of adulthood is a matter of state and local law. This means that who is legally considered a child may vary from state to state; in a large majority of states eighteen years of age is the legal age of adulthood, but this is not true in every state, locality, or territory. Also, there may be exceptions to who is considered a child and additional laws in places that define emancipated minors. The definition of “children” also takes into account the particular treatments or procedures involved in the proposed research; for example, in some places individuals who are sixteen years of age may legally consent to certain medical treatments, and so if the involvement of human subjects in a proposed research activity consists of these treatments, then they may be considered as adults for that purpose. If a proposed activity includes something for which the subject has not yet reached the legal age of consent, however, that person must be considered a child.

When doing research in locations outside the United States, the researcher needs to know what the applicable laws are concerning who is a "child."

Parental Permission and Child Assent

When conducting research with children, consider whether only the child, or both the child and the parent (or guardian), will be research participants.  For example, if you will ask the parent to fill out a questionnaire about their child as part of your research study and also ask the child to participate in research tasks, the parent and child are both research participants.  In such cases, you need to obtain the parent's consent to the parent's own participation in the research, the parent's permission for the child to participate, and (if appropriate) the child's assent to participate in the research.  A combined form to obtain the parent's consent to the parent's own participation and permission for the child to participate is often appropriate in such situations, so long as you clearly explain which research tasks pertain to the parent and which tasks pertain to the child and clearly document the adult's consent to his/her own participation and permission for his/her child to participate.

"Assent" means a child's affirmative agreement to participate in research.  Mere failure to object does not constitute assent. (45 CFR 46.402(b)).  This means the child must actively show his or her willingness to participate in the research, rather than just complying with directions to participate and not resisting in any way.  The explanation of the research should be tailored to the age and developmental capabilities of the children who are being asked to participate in the research.  If your study will include children in a wide age range, you need to consider what is an appropriate assent process for the various ages of children in your study.

The regulations on human subjects research permit the IRB to waive assent if the capability of some or all of the children is so limited that they cannot reasonably be consulted.  So, for example, if a study will include very young children who would not be able to understand and give meaningful agreement to participate in a study, the researcher can request that the IRB waive the assent requirement for children who would not have the capability to provide meaningful assent. 

The process of asking a child to participate in research should be carefully planned and implemented, using age-appropriate language and methods, for any child who is capable of understanding and providing assent.  If a child is considered capable of being involved in the informational process (regardless of age), at least a simple verbal explanation of what will happen to him/her and the opportunity for questions and discussion should be given.  An appropriate assent form should be used when feasible -- assent forms should be written at a level of education and maturity appropriate to the youngest potential subjects in the age range, and the information delivered using suitable methods.  In most cases, 7 years of age is a reasonable minimum for a child with normal cognitive development to be capable of participating in a meaningful written assent process.

Research with adolescents: Depending on the complexity of the study and the condition/capacity of the adolescent participants, an adolescent assent form may be very similar to the parent permission form or it may need to be somewhat simpler than the adult's form.  In situations where the parental permission form will be identical to the adolescent assent form, the researcher may propose using one parental permission/child assent form, with signature lines for both the parent and the adolescent.