Also known as: reasonable expectation of privacy · reasonable expectation of privacy test · REOP · Katz test
Written by attorneys · grounded in primary & secondary sources — see below
A standard used to determine whether government conduct constitutes a search under the Fourth Amendment. The test asks whether a person has exhibited an actual subjective expectation of privacy that society is prepared to recognize as reasonable. Government action that violates such an expectation is a search requiring a warrant or an established exception.
Rita Russell carried her phone for months while meeting sources. Agents obtained four months of her historical cell-site records from the carrier using only a statutory order. The records mapped her daily locations in detail. Because individuals retain a reasonable expectation of privacy in such pervasive long-term location data, the acquisition was a search.
Ruby Rivera stayed overnight at a friend's apartment with permission. Officers entered the apartment without a warrant and seized items. Rivera moved to suppress the evidence. An overnight guest holds a reasonable expectation of privacy in the host's home and may challenge the search.
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Regina Robinson entered a public phone booth and closed the door. Agents attached a listening device to the outside and recorded her call. The recording captured words she intended to keep private. The Fourth Amendment protects people rather than places when a reasonable expectation of privacy exists.
Ricardo Rojas was arrested after a shooting in his apartment. Officers remained for days and conducted a full search without a warrant. Rojas challenged the extended search. A reasonable expectation of privacy persists in a private residence even after a homicide, requiring a warrant for further investigation.
Rosalind Reed operated an auto repair shop subject to state inspection rules. Officers entered without a warrant and examined vehicle records. Reed claimed a privacy interest in the documents. Administrative searches of closely regulated businesses may proceed under reduced expectations of privacy when statutory procedures are followed.
Ryan Roberts placed calls from his home phone. Police obtained a list of dialed numbers from the telephone company without a warrant. Roberts argued the list invaded his privacy. A person who voluntarily conveys numbers to the carrier assumes the risk that the company will share them, so no reasonable expectation of privacy attaches.
A person must first exhibit an actual subjective expectation of privacy. That expectation must then be one society recognizes as reasonable. Conduct that violates such an expectation constitutes a search under the Fourth Amendment.
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An overnight guest generally possesses a reasonable expectation of privacy in the host's home. That interest allows the guest to contest a warrantless search under the Fourth Amendment.
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Individuals retain a reasonable expectation of privacy in extensive historical cell-site location information even though carriers store the records. The government therefore must obtain a warrant supported by probable cause to access months of such data.
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Long-term cell-site data reveals pervasive and detailed movements that differ in kind from ordinary business records. The comprehensive nature of the tracking supports a reasonable expectation of privacy despite storage by the carrier.
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…now be overruled; its limitation on Fourth Amendment protection is, in the present day, bad physics as well as bad law, for reasonable expectations of privacy may be defeated by electronic as well as physical invasion. Finally, I do not read the Court's opinion to declare that no interception of a conversation one-half of which occurs in a…