Real estate appraisal, property valuation or land valuation is the process of valuing real property. The value usually sought is the property’s market value. Appraisals are needed because compared to, say, corporate stock, real estate transactions occur very infrequently. Not only that, but every property is different from the next, a factor that doesn’t affect assets like corporate stock. Furthermore, all properties differ from each other in their location – which is an important factor in their value. So a centralized Walrasian auction setting can’t exist for the trading of property assets, such as exists to trade corporate stock (i.e. a stock market/exchange). This product differentiation and lack of frequent trading, unlike stocks, means that specialist qualified appraisers are needed to advise on the value of a property. The appraiser usually provides a written report on this value to his or her client. These reports are used as the basis for mortgage loans, for settling estates and divorces, for tax matters, and so on. Sometimes the appraisal report is used by both parties to set the sale price of the property appraised.
Appraisal is the third and most insightful stage in using formal decision methods. The objective of the appraisal stage is for the decision maker to develop insight into the decision and determine a clear course of action. Much of the insight developed in this stage results from exploring the implications of the formal decision model developed during the formulation stage (i.e., from mining the model). Central to these implications is the formal recommendation for action calculated during the evaluation stage. Other implications include various forms of Sensitivity of the recommendation to various components of the decision model. Insight may also result from discussion of the key aspects of the reasoning that led to the formal decision model (i.e., by justifying the model). Possible actions following the appraisal stage include implementing the recommended course of action, revising the formal model and reevaluating it, or abandoning the analysis and doing something else.
Justifying a decision model entails exploring and explaining the reasoning that led to the formulation of particular aspects of the decision model.
Mining a decision model entails extracting information (e.g., sensitivity, value of prediction, and value of revelation) from a given decision model.