National Intelligence Estimates (NIEs) are United States federal government documents that are the authoritative assessment of the Director of National Intelligence (DNI) on intelligence related to a particular national security issue. NIEs are produced by the National Intelligence Council and express the coordinated judgments of the United States Intelligence Community, the group of 18 U.S. intelligence agencies. NIEs are classified documents prepared for policymakers. General overview NIEs are considered to be "estimative" products, in that they present what intelligence analysts estimate may be the course of future events. Coordination of NIEs involves not only trying to resolve any inter-agency differences, but also assigning confidence levels to the key judgments and rigorously evaluating the sourcing for them. Each NIE is reviewed and approved for dissemination by the National Intelligence Board (NIB), which comprises the DNI and other senior leaders within the Intelligence Community. National Intelligence Estimates were first produced in 1950 by the Office of National Estimates. This office was superseded in 1973 by National Intelligence Officers. This group of experts became the National Intelligence Council in 1979. In the early years, the National Intelligence Council reported to the Director of Central Intelligence in his role as the head of the Intelligence Community; however, in 2005, the Director of National Intelligence became the head of the Intelligence Community. The Intelligence Community's faulty assessments on Iraqi WMD in 2002 highlights the role Congress plays in promoting the analytic rigor and utility of strategic intelligence assessments, such as National Intelligence Estimates. Production of NIEs Senior civilian and military policymakers, including congressional leaders, typically request NIEs. Before a NIE is drafted, the relevant National Intelligence Officer (NIO) produces a concept paper or 'terms of reference' (TOR) and circulates it throughout the IC for comment. The TOR defines the key estimative questions, determines drafting responsibilities, and sets the drafting and publication schedule. Several IC analysts from different agencies produce the initial text of the estimate. The NIC then meets to critique the draft before it is circulated to the broader IC. Representatives from the relevant IC agencies meet to hone and coordinate line-by-line the full text of the NIE. Working with their agencies, representatives also assign the confidence levels to each key judgment. IC representatives discuss the quality of sources with intelligence collectors to ensure the draft does not contain erroneous information. Challenges to the production of NIEs The IC must overcome several challenges to