Harnessing the persuasive potential of data: The combinatory effects of data visualization and interactive narratives on obesity perceptions and policy attitudes. Data visualization has become a useful tool for website designers to effectively present complicated statistical information. In the context of health communication, however, the collective nature of aggregated data may hinder users from empathizing with individuals who suffer from a health issue. This study attempts to provide a solution to the limitation, by adding an interactive personal narrative to visualization of obesity data. Given the lack of empirical research that investigates why data visualization influences user engagement, the current study examines interactivity as an underlying mechanism. The level of interactivity in data visualization (low vs. high) was varied, along with the level of interactivity in a narrative of an obese character (low vs. high) in a 2 × 2 factorial-design experiment with 385 valid participants. Results showed that increased message interactivity for the narrative, presented with increased modality interactivity for data visualization, led to a greater empathic perception of obese individuals’ hardships and greater perceived severity of obesity, and less defensive responses to the website. As a result, high interactivity in data visualization showed significant indirect effects on participants’ attitudes toward policy change, only when presented with the highly interactive narrative.