Should you place three pie charts side by side, or should you avoid pie charts altogether? Publicly available visualization style guides offer contradictory answers to such questions. Despite their growing influence on how people encounter data, these guides are seldom studied as a collective phenomenon. Addressing this gap, this paper presents the first systematic analysis of 53 publicly accessible visualization style guides from diverse domains, including journalism, government, non-profit, corporate, and academic sectors. We build a standardized corpus, conduct a multi-method analysis that reveals both consensus and contradiction, and develop a companion Guidelines Explorer to support transparency and future use. This work sheds light on organizational visualization design norms and provides a foundation for future work that helps bridge the gap between academic and industry practices. In doing so, we help reframe style guides as sociotechnical artifacts that encode values as much as design rules.
ACM CHI Conference on Human Factors in Computing Systems