possession of the property. This is sometimes the case with property in a divorce settlement or a legal judgment. Mass appraisal and automated valuation models Automated valuation models (AVMs) are growing in acceptance. These rely on statistical models such as multiple regression analysis, machine learning algorithms or geographic information systems (GIS). While AVMs can be quite accurate, particularly when used in a very homogeneous area, there is also evidence that AVMs are not accurate in other instances such as when they are used in rural areas, or when the appraised property does not conform well to the neighborhood. Computer-assisted mass appraisal (CAMA) is a generic term for any software package used by government agencies to help establish real estate appraisals for property tax calculations. A CAMA is a system of appraising property, usually only certain types of real property, that incorporates computer-supported statistical analyses such as multiple regression analysis and adaptive estimation procedure to assist the appraiser in estimating value. Geographic-assisted mass appraisal (GAMA) is a generic term for any GIS-centric software package used by government agencies to help establish real estate appraisals for property tax calculations. Spatial-CAMA (SCAMA) is a general term for mass appraisal where spatial data is used with spatial dependence or spatial heterogeneity models. Spatial Lag Model (SLM) and Spatial Autoregressive Moving Average (SARMA) fall under spatial dependence while Geographically Weighted Regression Models (GWR) falls under spatial heterogeneity. Governing authorities and professional organizations International The various U.S. appraisal groups and international professional appraisal organizations have started collaborating in recent years towards the development of International Valuation Standards. This will facilitate global real estate appraisal standards, a much-needed adjunct to real estate investment portfolios which cross national boundaries. Some appraisal groups are already international organizations and thus, to some extent, already incorporate some level of global standards. The International Valuation Standards Council (IVSC) is a non-governmental organization (NGO) member of the United Nations with membership that encompasses all the major national valuation standard-setters and professional associations from 150 different countries (including the Appraisal Institute, the American Society of Appraisers, the RICS, the [Practising Valuers Association of India] and the Appraisal Institute of Canada). IVSC publishes the International Valuation Standards (IVS), now in its 12th edition. Germany In Germany, real estate appraisal is known as real estate valuation (Immobilienbewertung). Real estate appraisers (Immobilienbewerter or Gutachter) can qualify to become a Öffentlich bestellter und vereidigter Sachverständiger (officially appointed and