Data substitution is a technique used in data management where sensitive information is replaced with non-sensitive equivalents. This process helps protect personal or confidential data while still allowing for analysis and processing. For example, a person's name might be replaced with a unique identifier, ensuring privacy while maintaining the dataset's usability. This method is commonly employed in fields like healthcare and finance, where protecting individual privacy is crucial. By using data substitution, organizations can share and analyze data without exposing sensitive information, thus complying with regulations like GDPR and enhancing data security.