OPEN SOURCES

Unclassified sources of information are termed “open source.” These include the type of data that can be gleaned from newspapers, scientific journals, specialist publications, and the internet. Whereas some intelligence agencies have specific open source sections to exploit this material, it is generally estimated that 80 percent of intelligence supplied by intelligence agencies has been derived from open sources. Information from open sources may be combined to become a classified item. For example, where an agency’s premises may be known, and the local office employment density regulations are available, it may be possible to calculate accurately the personnel strength in a particular building, a figure that itself may be classified.