Voluntariness begins with recruitment. Potential subjects must not feel that they have been coerced into participating, nor must they fear the loss of some benefit to which they are otherwise entitled if they choose not to participate (such as on-going support by a social agency).
Special care must be taken if the person doing the recruiting is a person who is in a position of authority (such as a teacher recruiting his or her own students) or makes decisions about the provision of services (such as a director of a training clinic). It is the investigator's responsibility to ensure that a person's decision to participate or not will have no other effect on an existing relationship.
The following recruitment situations need special consideration: