The Influence of Verbal and Non-Verbal Language Manipulations on Data Quality

Abstract

The problems concerning data quality lead to negative consequences for transport planning; every year many millions of euros are spent collecting data and developing and using travel models that are based on these data. This paper is the result of studies about the effects of some different combinations of languages, understanding that the early step for data quality is comprehension of the questionnaire. It has been hypothesized and demonstrated that a number of verbal and non-verbal languages and the visual presentation of response choices affect respondents’ perception and influences answers. Starting from this assumption, research has been developed to test different forms of languages on a well defined group of people using a self-administered questionnaire. To this aim the university staff working in the department of transport and students attending transport courses were chosen. The innovation in the design of the tests developed in the research is the use of a small group because each unit represents a reliable result concerning the people’s understanding of the question. The same questions, elaborated following different verbal and non verbal languages, were proposed to the interviewer in the same time period to avoid external effects influencing the people’s answers. The results of this experiment are really interesting and suggest that differences in question format also influence the responses of people with “high education” levels.