Mosaic effect

The mosaic effect, also called the mosaic theory, is the concept that aggregating multiple data sources can reveal sensitive or classified information that individual elements would not disclose. It originated in U.S. intelligence and national security law, where analysts warned that publicly available or unclassified fragments could, when combined, compromise operational secrecy or enable the identification of protected subjects. The concept has since shaped classification policy, especially through judicial deference in Freedom of Information Act (FOIA) cases and executive orders authorizing the withholding of information based on its cumulative impact.