Assessor Paul D. Petersen

Maricopa County Assessor's Office



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

The basis or cause for the value of a parcel.


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.