Data validation involves checking the accuracy, completeness, and quality of data to ensure it meets specified criteria and standards. This process typically includes verifying data types, formats, ranges, and relationships to identify and correct errors or inconsistencies. Techniques for data validation can be applied during data entry, integration, or preprocessing stages to prevent invalid data from entering systems or databases. Effective data validation helps maintain data integrity, improve decision-making, and ensure that data-driven applications function correctly. It is essential for maintaining high-quality data and supporting reliable analytics and reporting.