The problems concerning data quality lead to negative consequences for transport planning, thus an important focus is to define some guidelines to obtain high quality data from transport surveys. This concept, became evident in the last years, has been clearly affirmed in the International Conference on Survey Quality and Innovation (2001), where the need to define some minimum standards has been specified, also if not any element has been given yet. One of the key elements of the survey on which is possible to work is the Questionnaire Instrument Design, and in this paper we want to begin individuating which tools can serve as a base for the standardization. Anyway this section of the survey design has to be left open, because the matter is making continue progresses as Stopher highlighted (Stopher P. R., Developing standars of transport survey quality. Transport Survey Quality and Innovation, Pergamon Press: Oxford, 2003) when showed the need of having more graphical instructions and simplifications of the tools to give less explanations to the respondents. The first section of the paper is devoted to analyse the questionnaire instrument design, defined above as the base from which starting the standardization. The instruments analysed in this paper will be the verbal and not verbal languages as 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 influence answers. The second section of the work deals with the survey developed to test different forms of languages on a well defined group of people using a self-administered questionnaire. At this aim the university staff working in the department of transport and students attending transport courses have been chosen. The last section is focused on the analysis of the results obtained from the test on the sample that allow for the definition of the first elements useful for the standardization. (Author/publisher)
Abstract