The objective of the Data Challenge courses is to teach students how to perform large-scale data-driven analyses themselves, combining the technical skills acquired earlier in the Data Science program with insights gained in methodological courses. Data Challenge 3 is the final course in this series and shall familiarize students with the skills of designing and executing a data analysis on a complex data source with time-related data from multiple angles for a public stakeholder (governance or society). The focus is on exploring complex, unknown data sources, developing analysis hypothesis with stakeholders, conduct the analysis, and visualizing and communicating complex analyses in an understandable way to a public stakeholder, and reflecting on the choices and their impact on the stakeholder.