Data visualization consultants measure success by assessing user engagement, business outcomes, and feedback. They track how frequently dashboards are accessed, how often users interact with specific visuals, and whether stakeholders are able to derive actionable insights. Data visualization consultant also evaluate whether visualizations help improve decision-making, streamline operations, or uncover new opportunities. Regular feedback sessions with clients allow them to make adjustments based on real-world use cases, ensuring that visualizations continue to meet evolving business needs and provide tangible value over time.