Ask Humans or AI? Exploring Their Roles in Visualization Troubleshooting

Visualization authoring is an iterative process requiring users to modify parameters like color schemes and data transformations to achieve desired aesthetics and effectively convey insights. Due to the complexity of these adjustments, users often create defective visualizations and require troubleshooting support. In this paper, we examine two primary approaches for visualization troubleshooting: (1) Human-assisted support via forums, where users receive advice from other individuals, and (2) AI-assisted support using large language models (LLMs). Our goal is to understand the strengths and limitations of each approach in supporting visualization troubleshooting tasks. To this end, we collected 889 Vega-Lite cases from Stack Overflow. We then conducted a comprehensive analysis to understand the types of questions users ask, the effectiveness of human and AI guidance, and the impact of supplementary resources, such as documentation and examples, on troubleshooting outcomes. Our findings reveal a striking contrast between human- and AI-assisted troubleshooting: Human-assisted troubleshooting provides tailored, context-sensitive advice but often varies in response quality, while AI-assisted troubleshooting offers rapid feedback but often requires additional contextual resources to achieve desired results.