False preconceptions about users can result in poor design, product development, and marketing decisions, so rectifying these preconceptions is essential for organizations. This research quantitatively evaluates the ability of data-driven personas to alter decision makers’ preconceptions about their online social media users. We conduct a within-participant experiment of 31 professionals carrying out a workplace task scenario. The participants’ conceptions of user attributes are recorded both before and after interacting with personas created from real user analytics data. Using statistical analysis to compare the responses, we find that personas had a significant effect on changing preconceptions about the audience segments. After interacting with personas, 81% of the participants changed their preconceptions of the audience, and 94% of the participants maintained or increased the accuracy of their perceptions of the audience after engaging with the personas. Moreover, the confidence of the participants in their responses increased. However, two participants did not change their preconceptions even when faced with contradictory factual information, which highlights the need for accompanying initiatives to align user preconceptions with user data fully.