Methods of designing data collection forms, particularly questionnaires, and methods of selecting samples from which to collect data have been discussed. Ways of coping with the most common problems that endanger accurate results have been described. But no matter how carefully a sample is drawn or a questionnaire designed, the data collected will not be accurate unless field force executes its job properly. As it is usually performed, fieldwork is one of the major sources of error in the typical research project – especially in questionnaire studies.
In telephone and personal interviews, an interviewer typically selects the person to interview, asks questions, and records the answers. Errors occur at each step. Electronic and computer developments are helping organize and mechanize some aspects of the process, thus reducing errors but perhaps adding new ones. The increased concern with privacy in modern society and the growing volume of telephone and mail intrusions are causing an increase in the number of respondents who reuse to cooperate, thus adding another potential source of error.
In addition to the above there are many less understood sources of error. To be able to appraise the validity and reliability of data collected through interviewing it is necessary to know the procedures used to collect data in the field. This article describes the procedures and examines how one can best cope with the problems encountered.
Research directors have two major alternatives for getting their fieldwork done – they can develop their own organizations or they can contract with a field work agency to do the job. In either case it is a difficult and costly step in the research process. Field work involves the selection, training, supervision and evaluation of individuals who collect data in the field. Data collection may be by interview or observation; but since the problems are greater in the interview process, the following discussion is primarily in terms of interviewing by telephone and in person. Mail surveys do not have these problems.
Most fieldwork organizations now have a central location from which they can do telephone interviews nationwide, and they can maintain a full time staff of interviewers who are well trained and experienced. This set up may be combined with “store” space in a shopping center where personal interviews are conducted and were full time staff is available for that purpose. These interviewers are able to handle many field work assignments and, with such centralization the data collection process can be loosely monitored.
When telephone interviewing is computer assisted, the paper questionnaire is replaced with a video screen. The questionnaire is entered into the computer in such a way that the questions come on the screen in proper sequence. If the appropriate next question is determined by the answer to the last one, the computer can be programmed to ensure that this happens. Interviewers read the questions and either type in the answers or use “light pens” to mark the answers on the video screen. This procedure has the advantage of controlling the questionnaire and having the data entered in the computer directly so that at any time the results can be summarized quickly.
When a project is ready for data collection, interviewers are assembled for training at the telephone interviewing site. Training in this case may involve instruction on using the computer as well as on the project itself. A supervisor can observe the work of individual interviewers on a master screen that shows what is on a given interviewer’s screen while what is being said comes over an audio monitor.