Waffster: Hierarchical waffle charts for budget visualization.

Understanding and consuming public budget data is a key issue, helping citizens in gaining insight into their democratic and political systems. The goal of this work is to present Waffster, a user-friendly representation supporting the understanding of such data. The proposed representation enables the browsing, searching, comparing, and presenting of the hierarchically arranged components and quantities in budgets. In this paper, we first conduct a thorough survey of online public budget visualizations. Then, in collaboration with Le Devoir, a Canadian daily newspaper, we propose a novel unit-based hierarchical design based on waffle charts. We evaluate this design using a controlled user study to compare it to a tree-map based layout, and a case study conducted with Le Devoir during the provincial election campaign in Quebec of 2018.