Allocation by Abstraction is a method used in real property appraisal for estimating the value of land on a parcel that has been improved with buildings or other structures, particularly where sales of comparable vacant land are scarce. It combines two related techniques: allocation, which divides a property’s total sale price between land and improvements using a typical land-to-property value ratio drawn from the local market, and abstraction (also called extraction), which arrives at land value by subtracting the depreciated replacement or reproduction cost of the improvements from the property’s total sale price, leaving the residual figure attributable to the land. For example, if a property sold for $400,000 and the improvements are estimated to have a depreciated cost of $280,000, the abstracted land value would be $120,000. The approach is most reliable where improvements are relatively new or easily valued, since depreciation estimates on older structures introduce greater uncertainty. It is commonly applied in mass appraisal for property taxation, in rural or built-out areas lacking vacant land sales, and in professional appraisal reports alongside the more preferred sales comparison approach.
Allocation by Abstraction
