AVM Glossary

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AJAX progress indicator
  • f

  • The legal process by which a lien on a property is enforced.
  • A table showing the number or percentage of observations falling in the boundaries of a given set of classes. Used in ratio studies to summarize the distribution of the individual ratios. See class; histogram; and mode.
  • Loss in value of a property resulting from changes in tastes, preferences, technical innovations, or market standards.
  • The ability of improvements to satisfy market standards and demands.
  • A land measure of 1/8 mile or ten chains or forty rods.
  • g

  • A form of bar chart used in project management. Each element (task) of a project is represented by a horizontal bar. The bars are placed on the chart according to a time scale. The left end of each bar indicates when the task is to begin. The length of each bar indicates the duration of the task. The right end of each bar indicates when the task is to be completed.
  • Given authoritative recognition by professional bodies such as the Financial Accounting Standards Board and its Generally Accepted Accounting Principles (GAAP).
  • A code used to locate or identify a point, such as the center of a parcel of real estate, geographically. The code is composed of the east - West and north - South coordinates of the point relative to some standard point of reference.
  • Geographical referencing or coding of data.
  • (1) A database management system used to store, retrieve, manipulate, analyze, and display spatial information. (2) One type of computerized mapping system capable of integrating spatial data (land information) and attribute data among different layers on a base map.
  • A measure of central tendency computed by multiplying the values of all of the observations by one another and then taking the result to an exponent equal to one divided by the number of observations. The geometric mean is particularly appropriate when a typical rate of change is being calculated, such as an inflation rate or a cost index.
  • A statistical estimate of the amount, and hence the importance, of the errors or residuals for all the predicted and actual values of a variable. In regression analysis, for example, goodness of fit indicates how much of the variation between independent variables (property characteristics) and the dependent variable (sales prices) is explained by the independent variables chosen for the AVM.
  • The number of valuations delivered relative to the total number of property addresses in the test sample; usually expressed as a percentage (e.g., 1,000 properties were submitted to an AVM and 600 properties were returned for a 60% gross hit rate).
  • h

  • The reciprocal of the arithmetic mean of the reciprocals of each value in the data set. The harmonic mean ratio is less affected by extreme values in the data set than the arithmetic mean or the geometric mean.
  • The term hedonic model broadly refers to a class of property-specific AVMs that examine housing characteristics (both physical and locational) to estimate a subject’s market value. These models operate under the assumption that a house is a composite good comprising many traits that appeal to consumers in varying degrees. Through the application of direct market and comparable sales analyses, hedonic AVMs attempt to quantify the extent to which certain attributes contribute to a property’s overall value, and then develop value conclusions based on these findings.
  • An analytical model used to quantify the pricing tradeoff between measurable product capacity and intangible attributes such as an amenity feature, design, or reputation. See also isoquant.
  • Hedonic pricing attempts to take observations on the overall good or service and obtain implicit prices for the goods and services. Prices are measured in terms of quantity and quality. When valuing real property the spatial attributes and property specific attributes are valued in a single model. Calibration of the attribute components is performed statistically by regressing the overall price onto the characteristics.
  • A multivariate analysis that predicts and explains the value of individual characteristics bundled together to form a good or service; based on the marginal utility of good character and the desirability of that good.
  • Unlike; without interrelation. The opposite of homogeneous.
  • Non-constant variance, specifically, in regression analysis a tendency for the absolute errors to increase (fan out) as the dependent variable increases.
  • A principle of appraisal and assessment requiring that each property be appraised as though it were being put to its most profitable use (highest possible present net worth), given probable legal, physical, and financial constraints. The principle entails first identifying the most appropriate market and, second, the most profitable use within that market. The concept is most commonly discussed in connection with underutilized land.
  • A bar chart or graph of a frequency distribution in which the frequencies of the various classes are indicated by horizontal or vertical bars whose lengths are proportional to the number or percentage of observations in each class.
  • The number of years elapsed since an original structure was built. Synonyms are actual age and chronological age. See cost, original.
  • The percentage of properties that have been valued by the AVM. See also "Gross Hit Rate" and "Adjusted Hit Rate."
  • Part of a set of data set aside for testing the results of analysis.
  • Also called a "hold-out sample." A dataset drawn from the same population as the training dataset that is not used to calculate the AVM valuations. The holdout dataset is used for testing. Cross-validation techniques allow sales in the training dataset to be reused as the holdout set.
  • Possessing the quality of being alike in nature and therefore comparable with respect to the parts or elements; said of data if two or more sets of data seem drawn from the same population; also said of data if the data are of the same type (that is, if counts, ranks, and measures are not all mixed together).
  • A model that provides an estimate of a property’s value as a function of time. HPIs find the house price path most consistent with observed appreciation or depreciation rates in a region. Typically referred to as an “index of home price appreciation,” indexes are mathematical algorithms that ad- just property values up or down to reflect price changes over time. These models are price-specific and not property-specific.
  • Models that incorporate both additive and multiplicative components. See also additive model, hedonic models and multiplicative model.
  • Models that incorporate both additive and multiplicative components. See also additive model, hedonic models and multiplicative model.


a)       AVMetrics

b)      AVMs 201: A Practical Guide to the Implementation of Automated Valuation Models, Jim Kirchmeyer, 2008.

c)       IAAO 2015, Glossary for Property Appraisal and Assessment, 2015. (2013 online: https://www.iaao.org/media/Pubs/IAAO_GLOSSARY.pdf )

d)      Collateral Assessment & Technologies Committee, Summary of Definitions & Terms, 2006.

e)      Joint Industry Task Force on AVMs, IAAO Standard on AVM Glossary, September 2003. https://www.iaao.org/media/standards/AVM_STANDARD.pdf

f)        Appraisal Institute, Joint Industry Task Force on Automated Valuation Models, Work Group Terminology, 2005.

g) Merriam-Webster (https://www.merriam-webster.com/)