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Definition

Fourth Amendment

The mosaic theory is

[t]he concept that apparently harmless pieces of information when assembled together could reveal a damaging picture.[1]

Overview

As with the "mosaic theory" often invoked by the Government in cases involving national security information, "What may seem trivial to the uninformed, may appear of great moment to one who has a broad view of the scene."[2]

Under the mosaic theory of the Fourth Amendment, courts evaluate a collective sequence of government activity as an aggregated whole to consider whether the sequence amounts to a search. Under the theory, searches are "analyzed as a collective sequence of steps rather than as individual steps."[3]

"The approach is based on the observation that comprehensive aggregation of even seemingly innocuous data reveals greater insight than consideration of each piece of information in isolation. Over time, discrete units of surveillance data can be processed to create a mosaic of habits, relationships, and much more. Consequently, a Fourth Amendment analysis that focuses only on the government's collection of discrete units of data fails to appreciate the true harm of long-term surveillance — the composite."[4]

References

  1. 32 C.F.R. 701.31.
  2. United States v. Maynard, 615 F.3d 544, 562 (D.C. Cir. 2010) (citation omitted), aff'd sub nom. United States v. Jones, 132 S. Ct. 945 (2012).
  3. Orin Kerr, "The Mosaic Theory of the Fourth Amendment," 111 Mich. L. Rev. 311, 312 (2012).
  4. Steven M. Bellovin, Renée M. Hutchins, Tony Jebara & Sebastian Zimmeck, "When Enough Is Enough: Location Tracking, Mosaic Theory, and Machine Learning," 8 New York Univ. J. of Law & Liberty 555, 591 (2014) (full-text).
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