For a larger glossary of many terms used in property appraisal, please see the International Association of Assessing Officers' Glossary for Property Appraisal and Assessment .


The process of estimating the market value, insurable value, investment value, or some other properly defined value of an identified interest or interests in a specific parcel or parcels of real estate as of a given date. Valuation is a term used interchangeably with appraisal.

Valuation Source

Where the parcel's latest value came from. Examples include Notices, Appeals, and Decisions.


The terms full value, full cash value, cash value, actual value and fair market value mean the price at which a property, if exposed for sale in the open market with a reasonable time for the seller to find a purchaser, would transfer for cash or its equivalent under prevailing market conditions between parties who have knowledge of the uses to which the property may be put, both seeking to maximize their gains and neither being in a position to take advantage of the exigencies of the other.

Value in Exchange

The amount an informed purchaser would offer in exchange for a property under given market conditions.

Value in Use

The value of property for a specific use.

Variable Proportions

Also called the law of decreasing returns, this states that as quantities of one productive service increases, the quantities of other productive services remaining fixed, the resulting increment of product will decrease after a certain point.