What is the purpose of a context filter in Tableau?

The purpose of a context filter in Tableau is to set the context for other filters, which improves performance by limiting the data that these subsequent filters have to process. When you designate a filter as a context filter, it creates a temporary table that contains only the data that meets the context filter's criteria. This means that any other filters applied afterward are processed only on this reduced dataset, which can significantly enhance query performance, especially when dealing with large datasets.

Context filters also play a crucial role in scenarios where the order of filters affects the results. By using a context filter, you ensure that the filters that depend on it will function as intended, providing accurate and relevant insights based on the initial data context established. This capability makes context filters a powerful tool in Tableau for optimizing performance and refining data analysis.