Interviewers as a Source of Error in Surveys

ALMOST every research man will concede that field work is one of the most serious sources of error in the typical research project, and some contend that it is the major source of error.1 Little is done on the typical project, however, to control this type of error. Part-time interviewers are used. Frequently they are on the staff of an independent field work organization. Their capabilities are seldom known by the research director. His only contact with them is likely to be through a written set of instructions which may be studied with varying degrees of care. Completed interviews are "edited" for mechanical procedure, and routine checks for cheating are made. The collected data are then punched into cards and are assumed to be correct. There is reason to believe that the field