(Part I of IV) Valuation analysts (“analysts”) are often asked to value special-purpose industrial and commercial property. These analyses may be developed for various purposes, including taxation purposes. This discussion focuses on the identification and measurement of economic obsolescence in the application of the cost approach to value such special-purpose property. This topic is particularly relevant to the unit principle appraisal of integrated and complex properties operating on a going-concern basis. Analysts and tax assessors often apply the unit principle of appraisal to value such complex industrial and commercial properties for state and local ad valorem tax appeal and litigation…