Governmental Tracking of Cell Phones and Vehicles: The Confluence of Privacy, Technology, and the Law (R42109, December 2011) — "This report will briefly survey Fourth Amendment law as it pertains to the government’s tracking programs. It will then summarize federal electronic surveillance statutes and the case law surrounding cell phone location tracking. Next, the report will describe the GPS-vehicle tracking cases and review the pending Supreme Court GPS tracking case, United States v. Jones. Finally, the report will summarize the geolocation and electronic surveillance legislation introduced in the 112th Congress." (25 pp. PDF)

Data Mining and Homeland Security: An Overview (RL31798, August 2008) — "Data mining has become one of the key features of many homeland security initiatives. Often used as a means for detecting fraud, assessing risk, and product retailing, data mining involves the use of data analysis tools to discover previously unknown, valid patterns and relationships in large data sets…. As with other aspects of data mining, while technological capabilities are important, there are other implementation and oversight issues that can influence the success of a project’s outcome." (41 pp. PDF)

Privacy: Total Information Awareness Programs and Related Information Access, Collection, and Protection Laws (RL31730, March 2003) — "This report describes current laws and safeguards to protect the privacy of personal information, the required legal process for officials who seek access to information, and the provisions currently in place that permit access and dissemination of information for law enforcement, intelligence, and terrorism purposes." (35 pp. PDF)

For Further Information – See the GAO Reports on collection methods.