Abstract: The most widespread quantitative tool for social scientific data gathering is a survey. Surveys –if designed and executed properly- allow for the projection of information gathered among a sample of respondents to the broader population to which this sample belongs. The focus is on gathering data which is generalizable to a larger population, through standardized procedures and questions. However, there are important variations in how surveys can be set up and applied, ranging from the sampling method to the content of the questions and the ways in which they will be presented to respondents. The development of quantitative tools in RadoNorm WP6 therefore aims to design and test surveys which provide implementable and valid means for assessing populations’ perceptions, opinions, awareness, motivations, attitudes and behaviours with regard to radon and NORM. Surveys will be applied and tested in eight different European countries. A first test, the pilot study, took place at the end of 2020 in Belgium. This working document reports results from this pilot study on public opinion survey(s) conducted in Belgium. The document provides information of a technical / statistical nature in order to evaluate and improve radon measurement scales, in general, and RadoNorm questionnaires, in particular.