Conati, CristinaCarenini, GiuseppeHoque, EnamulSteichen, BenToker, DereckH. Carr, P. Rheingans, and H. Schumann2015-03-032015-03-0320141467-8659https://doi.org/10.1111/cgf.12393There is increasing evidence that user characteristics can have a significant impact on visualization effectiveness, suggesting that visualizations could be designed to better fit each user's specific needs. Most studies to date, how-ever, have looked at static visualizations. Studies considering interactive visualizations have only looked at a li-mited number of user characteristics, and consider either low-level tasks (e.g., value retrieval), or high-level tasks (in particular: discovery), but not both. This paper contributes to this line of work by looking at the impact of a large set of user characteristics on user performance with interactive visualizations, for both low and high-level tasks. We focus on interactive visualizations that support decision making, exemplified by a visualization known as Value Charts. We include in the study two versions of ValueCharts that differ in terms of layout, to ascertain whether layout mediates the impact of individual differences and could be considered as a form of personalization. Our key findings are that (i) performance with low and high-level tasks is affected by different user characteristics, and (ii) users with low visual working memory perform better with a horizontal layout. We discuss how these find-ings can inform the provision of personalized support to visualization processing.