Phase Three Consent

Ellwood P, Asher MI, Stewart AW and the ISAAC Phase III Study Group. The impact of the method of consent on response rates in the ISAAC time trends study. Int J Tuberc Lung Dis. 2010 Aug;14(8):1059-65.View Article

Consent & Confidentiality

At the outset of ISAAC Phase One, a great deal of importance was placed on protecting the identity of the participants and deciding on the most appropriate method of obtaining consent. As well as maintaining confidentiality of the information given by the participants a high response rate was expected (≥ 80% for adolescents and ≥70% for children). In Phase One most centres had an ethics committee that viewed and approved the protocol prior to starting the study. Those centres that did not have an ethics committee used some other authorisation, such as the Ministry of Education to approve the study.

Although identifying information was obtained from the participants, this demographic information was only used to ensure participant details were correct and was checked against the school records for accuracy. The questions asked for the participant’s name and school name, their age, date of birth, gender, home address, ethnicity and the date the questionnaire was completed. When these details had been certified correct the participant became identified by a unique ID number by centre number, school number, and participant number. These numbers were entered into the computer with the answers to the core questions on the symptom prevalence of asthma, rhinitis and eczema, providing total anonymity of participants.

Because of this anonymity and due to the innocuous nature of the questions asking about the symptom prevalence of asthma, rhinitis and eczema, most ethics committees approved the use of passive consent. This approach was also the recommended approach by the ISAAC Steering Committee. This involved, for the adolescent group, sending an information letter home to the parents informing them about the study and requesting they contact the researcher/s if they or the adolescent did not wish to participate. If they did not contact the researcher it was assumed they would take part in the study. For the children, the questionnaire was sent home to parents/guardians with the information letter requesting them to complete it and return it to school. Some ethics committees requested active consent from parents/guardians which involved getting parents/guardians to give written consent prior to the study taking place in the schools for the adolescents and for the children, prior to sending the questionnaire home for completion.

In Phase Three we found that some ethics committees had made a huge shift in their approach to how consent was obtained in research and developed new policies for using active consent for all types of research, whether it was clinical trials, or epidemiological surveys. This had an adverse effect on the response rates in some schools and participants, resulting in exclusions from Phase Three. This has been documented in a publication [Ellwood 2010](above right). We found that a higher response rate in questionnaire-based epidemiological studies is more likely if parents are not required to give active consent. This was more evident in the English language centres that had been used to the passive consent approach for this type of study. It also raises questions about the ethics of using active consent when it is not strictly necessary, which can lead to low response rates and exclusion, thus wasting valuable research funding and denying the involvement of those parents/adolescents that wish to participate.