In this study a number of terms are used in special contexts.
Verification defines the process of determining compliance or noncompliance with an agreement—or the accuracy of a declaration—based on analysis of the totality of information available from all sources.
Monitoring includes all activities conducted to gather information on the status of nuclear weapons and nuclear weapons associated facilities—whether declared or undeclared and whether subject to an agreement or not—including agreed multilateral technical means, National Technical Means, inspections, and other sources of information.
Multilateral technical means refers to information gathering and analytical capacities deployed by multinational bodies; for example, the IAEA currently deploys instrumentation, inspectors, and analytical capabilities related to the agency's responsibilities under the NPT and associated agreements.
National Technical Means (NTM) covers all nationally operated technical collection activities located outside the territory of a state under observation (including the space above its sensible atmosphere) capable of gathering information concerning that state’s compliance with an agreement.
Inspections cover formal visits by inspectors representing another government or international institution to a declared facility or suspect activity, or the permanent stationing of inspectors at a declared facility. Inspectors can employ agreed technical equipment or install agreed permanent surveillance equipment.
Other sources include open sources (newspapers, the Internet, historical documents and published technical papers), reports by travelers and defectors, “whistle blowers,” and clandestine human sources.