Depending on the ways of information visualization, information can be interpretable, easy to understand, and represented concisely and consistently. This study explores the effects of different information visualizations on decision quality in a Web environment by conducting a laboratory experiment. The results demonstrated that the effects of information visualizations on decision quality were significant. The findings suggest that information users in a Web environment can expect to improve their decision quality by enhancing information visualizations. This research extends a body of research examining not only the effects of factors that can be tied to human decision-making, but also the predictions of various information visualization usages in a Web environment.