What Are Data Quality Frameworks Like Great Expectations and Deequ? If you work with data, you've probably heard the names Great Expectations and Deequ mentioned. In short, they are both powerful, open-source frameworks used for data quality testing and validation . Think of them as "unit testing" for your data. Their main purpose is to help data engineers, analysts, and scientists ensure their data is accurate, complete, and reliable before it's ever used for analytics, machine learning models, or important business reports. These frameworks allow you to define rules about what your data should look like. For example: "This column should never be empty (null)." "All values in this column must be unique." "This number must be within a certain range (e.g., 1 to 100)." "This text must match a specific pattern (like an email address)." They then automatically test your data against these rules and al...