Journal of Property Tax Assessment & Administration


Computer-assisted mass appraisal (CAMA) systems are used by most North American assessment jurisdictions to provide estimates of market value. Automated valuation model (AVM) systems provide estimates of market value for financial institutions and other users of private-sector valuation services. Although CAMA and AVM systems are designed to provide services to different clients, there are many similarities between them. Both systems require appraisers and analysts to perform market analysis to develop their valuation formulas. Both are designed to calculate estimates of valuation for multiple properties. Both support programs with formulas or tables for rapidly calculating estimates of real estate value. Both calculate real estate property values one property at a time. Both provide some level of statistical quality. Moreover, both CAMA and AVM systems are enhanced through the use of statistical software and geographic information systems (GIS). This article demonstrates the effectiveness of using statistics for reviewing data, developing market models, and determining the statistical quality of model results. GIS technology enhances data review and market and locational analysis. This article advocates the use of statistical software and GIS to enhance appraisers’ market analysis abilities.

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Housing market - models, Geographic information systems