Sensitivity of National Fire Management Analysis System (NFMAS) Solutions to Changes in Interagency Initital Attack (IIAA) Input Data

A sensitivity analysis was conducted of the National Fire Management Analysis System (NFMAS) to better understand the relationship between data input and model output. After consultations with fire managers and researchers, five input variables were selected for sensitization: unit mission costs, average acre costs, net value change, production rates, and escaped fire limits. A random sample of 23 National Forests was selected, according to the distribution of forests within regions and fire frequency classes, on the basis of historical fire data. Database tables were manipulated, with each variable increased and decreased at six levels (±25, ±50, and +100 percent). The Interagency Initial Attack Assessment (IIAA) model was run at each successive level, generating a new set of output, cost plus net value change (C+NVC), for each sensitized variable. Results were analyzed statistically, and production rates and average acre costs were found to be the most influential, while unit mission costs was least influential. In general, greater sensitivity changes resulted in greater changes in C+NVC. The National Fire Management Analysis System (NFMAS) was designed in the late 1970's by Richard Chase, for use by the USDA Forest Service in strategic fire management and budget planning. It was later adopted by other fire-management agencies, including the USDI's Bureau of Land Management and the National Park Service. The NFMAS simulation model (NARTC 1997) currently consists of two software programs: Personal Computer Historical Analysis (PCHA), which provides historical weather and fire behavior data, and the Interagency Initial Attack Assessment (IIAA). IIAA (COMPUS 1997) is the analytical engine, a tool intended to help analyze various fire-management scenarios or program options that represent various combinations of fire-fighting resources and other budget items. The overriding purpose of IIAA analysis is to help identify the most efficient level (MEL) of funding for a given National Forest, that is, the program option associated with lowest sum of the presuppression budget, emergency fire-suppression costs, and net value change of resources (the sum of positive and negative resource effects). An administrative unit's initial attack organization will use these data in developing budget requests. NFMAS is applied to a sub-forest area, the fire management zone, and results are aggregated to produce Forest, Forest Service Region, and agencywide totals. This service-wide total is used as the basis for budget proposals. Management of NFMAS is a major undertaking in the Forest Service. Training sessions are held at the Marana, Arizona, facility. NFMAS training is received by selected Forest Service personnel, ranging from district fire management officers to upper level managers, and by personnel from USDI agencies and various state fire-fighting organizations. A NFMAS "certification” process is implemented at both the regional and forest levels. Certification involves inspection teams reviewing and revising data and procedures used by field personnel to help ensure compliance with national policy, promoting consistency between units. NFMAS-related databases are constructed, calibrated, and analyzed to identify the most efficient initial attack organization for each Forest. The budgets associated with those most-efficient organizations, MEL, become part of the Forest Service appropriations process. An abbreviated version of this paper was presented at the Symposium on Fire Economics, Policy, and Planning: Bottom Lines, April 5-9, 1999, San Diego, California. Project Leader and Computer Assistant, respectively, Econ­ omic Aspects of Ecosystem Management Research, Rocky Mountain Research Station, USDA Forest Service, 800 East Beckwith, P.O. Box 8089, Missoula, MT 59807; e-mail: eschuster/rmrs, missoula or Schuster Ervin/rmrs_missoula