There are different approaches to planning, each focusing on different requirements, authorities, levels of operation and specific organizational missions within the homeland security spectrum of operations. Capability-Based. This planning approach focuses on available personnel and resources that can be applied to address significant incidents. Requirements and capabilities are derived from the National Planning Scenarios, the National Homeland Security Plan, strategic planning, risk assessments, concepts of operations, and threat information. This capabilities-based planning approach and the National Preparedness Guidelines foster vertical and horizontal integration of Federal, State, local, and Tribal plans allowing State, local and Tribal capability assessments to inform Federal requirements and capabilities planning. Functional. A functional planning approach identifies a list of common tasks an organization must perform during an incident, an emergency, a specific event/activity or a directed requirement. They are created at all operational levels and formatted in accordance with the standards of the parent organization. They may be developed in response to HSPD/NSPD requirements, at the organization's senior leadership initiative, or in response to either national policy or a guidance document requirement. Scenario-Based. A scenario-based plan is developed from a National Planning Scenario; there are currently 15 National Planning Scenarios. These scenarios have been grouped into eight sets. National Planning Scenarios will be developed, updated, or amended as necessary at least every two years. This process will be informed by a risk-based analysis intended to focus planning efforts on the most likely or most dangerous threats to the homeland. Annex I to HSPD-8 specifically addresses this planning approach. (FEMA, Interim IPS (Draft 2.3), July 3, 2008 copy, pp. 2-10, 2-11)