Charts and graphs are ubiquitous in business documents, and most students in the author's business communication courses are well aware that they need to be able to create many different types of data representation. Most of them have had a great deal of experience working with spreadsheet applications, and they know how to manipulate data and present it in the various forms permitted by their software. However, they do not always understand how to make the most appropriate choice among those forms for a particular situation. To assist students in recognizing the salient features of charts and graphs, the author provides them with a collaborative in-class activity that asks them not only to create a set of visuals but also to justify their choices to their classmates. The activity begins with distribution of a mini-case study, presented in this article, that leads to the creation of two visuals. After the students have had time to create the visuals, each group presents its work to the class, explaining the reasoning behind its presentation. The discussion that ensues during the "justification" part of the activity consistently improves the students' understanding of the advantages and disadvantages of the various forms that data representations can take. (Contains 1 table.)