In the data collection process the research organization or the researcher need the services of field force, which consists of interviewers and supervisors. Mail surveys, mail panels, e-mail, and Internet surveys do not require field force. However, traditional telephone interviews, CATI, mall intercept interviews, and CAPI all require different number of field force. In-home personal interviews are problematic in this respect, because many interviewers work in many locations, continued supervision is impractical.
