The Five Major Subjects of American Intelligence Gathering

Collecting intelligence has always been the key to accomplishing the mission of intelligence work. The work used to accomplish these missions includes collecting information overtly, collecting information covertly, using technology to collect information, integrating information, and performing a comprehensive analysis of information.

The five major intelligence collection subjects recognized by the U.S. intelligence community are open source intelligence (OSINT), human intelligence (HUMINT), signal intelligence (SIGINT), geospatial intelligence (GEOINT), and measurement and signature intelligence (MASINT).

1. Open Source Intelligence

Open source intelligence refers to information and sources that are widely available, including sources from the media (newspapers, radio, television, social media, etc.), professional and scholarly records (papers, conferences, professional associations, etc.), and public data (government reports, hearings, etc.) meetings, speeches, etc.

Open source intelligence is often considered the preferred source of intelligence acquisition because of its ubiquity and broad sharing. Open source intelligence is openly available to all, and can be obtained, reviewed, and analyzed through legitimate means such as application, observation, or purchase.

2. Human intelligence

Human intelligence is the gathering of information from human sources. Gathering can be done overtly, such as when FBI agents interview witnesses or suspects, or covertly, such as through espionage.

In the United States, the Federal Bureau of Investigation (FBI) is responsible for human intelligence collection within the United States. The Central Intelligence Agency (CIA) is responsible for human intelligence collection outside the United States, but other U.S. agencies abroad also collect human intelligence. While human intelligence is a key collection discipline for the FBI, the FBI also gathers intelligence through other methods, including signals intelligence, measurements and signatures intelligence, and open source intelligence.

3. Signals Intelligence

Signals intelligence refers to electronic signals that can be collected by ships, aircraft, ground stations, or satellites. Communications intelligence (COMINT) is a type of signals intelligence that refers to the interception of communications between two parties. US signals intelligence satellites are designed and built by the National Reconnaissance Office, although the National Security Agency (NSA) is primarily responsible for conducting US signals intelligence activities.

4. Geospatial Intelligence

Geospatial intelligence is the analytical and visual representation of security-related activities on Earth. It is produced through the integration of imagery, image intelligence and geospatial information.

Image intelligence (IMINT) is also sometimes referred to as photo intelligence (PHOTINT). One of the earliest forms of imagery intelligence occurred during the Civil War, when soldiers were sent in balloons to gather intelligence about their surroundings. Imagery intelligence was practiced to a greater extent in World Wars I and II, when both sides took pictures from aircraft. Today, the National Reconnaissance Office designs, builds, and operates imagery satellites, while the National Geospatial-Intelligence Agency is primarily responsible for processing and using imagery.

5. Measurement and Signature Intelligence

Measurement and signature intelligence is a relatively little-known collection discipline that deals with weapons capabilities and industrial activity. Measurement and signature intelligence includes the advanced processing and use of data collected from aerial and airborne imagery intelligence and signals intelligence collection systems.

DIA's Central Office of Measurement and Signature Intelligence is the primary user of measurement and signature intelligence data. Measurement and signature intelligence has become increasingly important due to growing concerns about the existence and proliferation of WMD. For example, measurement and signature intelligence can be used to help identify chemical weapons or pinpoint specific characteristics of unknown weapon systems. As another example, the Chemical-Biological Sciences Division of the FBI Laboratories provides analysis to detect traces of chemical, biological, or nuclear materials to support the prevention, investigation, and prosecution of terrorist activities.