Data validation focuses on ensuring that data is accurate, consistent, and fit for analysis before it is used in reports or dashboards. Articles under this tag explore techniques for validating inputs, detecting errors, enforcing rules, and preventing inconsistencies using tools such as Excel and Power BI. Readers will find best practices, automation methods, and real-world examples that improve data quality and reduce reporting risk. Use this tag to understand how proper validation strengthens trust in analytics and decision-making.