Abstract
A major problem in education and visual information design is that, while tools to measure people's reading and writing ability with texts and numbers are ripe, the ability to properly process information from data graphics, an ability that can be called Visual Information Literacy, is still off the radar, and even less interest is apparently devoted to its evaluation. The purpose of this research is that of presenting an exploration of methods and tools towards the measurement of data graphics effectiveness and efficiency, and of proposing a definition of `Visual Information Literacy', together with the design of a model characterizing it as a developmental skills progression that covers the cognitive abilities activated when dealing with data graphics. A final goal of this paper is to report a first round of results assessing the validity of the model designed, by bringing statistical evidence that data graphics comprehension depends on the matching of users' ability and data graphics difficulty. The contribution of this paper is twofold: comparing the current research on Visual Information Literacy and advancing it by designing a model for its characterization to allow the design of a Visual Information Literacy measurement scale standard.