A questionnaire, as a basic tool of organization of scientific observation, consists of two schemas: a data schema that corresponds to the specifications and the conceptual determinations of scientific vocabulary and a communicative schema that organizes the communication between the scientists and respondents depending on the particular characteristics of the asked population. The objective of this paper is the design of a documentation model for the questions of a questionnaire that would allow the detection of similar questions throughout a database. Such a model can successfully manage the documentation problems of comparative longitudinal research, whereas the questions of a questionnaire are repeated and changed slightly or go unchanged through the waves. It can also help researchers that are concerned with secondary analysis, for the detection of similar questions of similar or even different studies.