ABSTRACT
Most of the data that come into the office of the survey analyst are based on one interview with each member of a group of people. The panel technique of repeated interviews with the same respondents, however, is not needed if the event or opinion to be traced is easily remembered, or if the time lapse involved is comparatively short. Memory is deceptive when there are conscious or unconscious desires of the respondent to distort the past. One-interview surveys will yield accurate results if the question refers to the time instrant at which the interview takes place. If the respondent is to recall events which extend over a time period one must rely on memory. Only through the panel can one avoid reliance on the respondent's memory, if one aims at data which refer to an extended period of time.
