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King County Department of Assessments

Fair, Equitable, and Understandable Property Valuations

Department of Assessments

500 Fourth Avenue,
Suite ADM-AS-0708,
Seattle, WA 98104

Office Hours:
Mon - Fri
8:30 a.m. to 4:30 p.m.

TEL: 206-296-7300
FAX: 206-296-5107
TTY: 206-296-7888

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Glossary of terms for commercial parcels

ACCESSORY IMPROVEMENTS
Improvements other than the principal buildings.

ADJUSTMENTS
Modifications in the reported value of a variable, such as sale price.  For example, adjustments can be used to estimate market value in the sales comparison approach by modifications for differences between comparable and subject properties.

AD VALOREM
IAccording to value.

AD VALOREM TAX
A tax levied in proportion to the value of the thing(s) being taxed.  Exclusive of exemptions, use-value assessment provisions, and the like, the property tax is an ad valorem tax.

ANTICIPATION, PRINCIPLE OF
Value is the present worth of all the anticipated future benefits to be derived from a property. The benefits, in the form of an income stream or amenities, are those benefits anticipated by the market.  The assessor should not allow personal opinion to influence the estimation of anticipated future benefits.  Prior sales and prior income streams are important only when the parallel the current actions of buyers, thus providing an indication of what may be expected in the future. The principle is related to the principle of change, which can sometimes make the prediction of future benefits difficult.

APPRAISAL RATIO
(1) The ratio of the appraised value to an indicator of market value.  (2) By extension, an estimated fractional relationship between the appraisals and market values of a group of properties.

APPRAISAL RATIO STUDY
A ratio study using independent appraisals as indicators of market value.

APPRAISAL-SALE PRICE RATIO
The ratio of the appraised value to the sale price (or adjusted sale price) of a property;  a simple indication of appraisal accuracy.

APPRAISAL STANDARDS BOARD
The division of the APPRAISAL FOUNDATION that develops, publishes, interprets, and amends the Uniform Standards of Professional Appraisal Practice on behalf of appraisers and users of appraisal services.

ASSESSMENT
(verb)  The official act of discovering, listing, and appraising property.   (noun) The value placed on property in the course of such act.

ASSESSMENT EQUITY
The degree to which assessments bear a consistent relationship to market value.

ASSESSMENT LEVEL
The common or overall ratio of assessed values to market values.

ASSESSMENT RATIO
(1) The fractional relationship an assessed value bears to the market value of the property in question. (2) By extension, the fractional relationship the total of the assessment roll bears to the total market value of all taxable property in a jurisdiction. See level of assessment.

ASSESSMENT-SALE PRICE RATIO
The ratio of the assessed value to the sale price (or adjusted sale price) of a property.

AVERAGE DEVIATION
The arithmetic mean of the absolute deviations of a set of numbers from a measure of central tendency, such as the median.  Taking absolute values is generally understood without being stated.   The average deviation of the numbers 4,6, and 10 about the median (6) is (2 +0+4)/3 =2.   The average deviation is used in computing the coefficient of dispersion.  (COD).