Empirische Analyse der Sensitivität und Gravität der Eingangsparameter im Residualwertverfahren (Residual Method) gem. ÖNORM B 1802-3 bei der Immobilienbewertung

In a few cases, a property valuation can only be performed by using the Residual Method due to the lack of other methods reflecting the market situation. In Austria this valuation method is standardized in ÖNORM B 1802-3. Research of international valuation literature shows that there is far-reaching agreement that the Residual Method is considered a highly sensitive method of valuation. From this, the general subsidiarity of the Residual Method compared to the classical methods of Comparison Approach, the Cost Approach or the Income Approach is derived. However, there is no scientifically comprehensive investigation of the question which variation of input parameters has a particularly strong influence on the residual. Also, a scientifically founded discussion of the varying sensitivity of the valuation result depending on the size ratio of the individual variables to the residual is missing until now. The purpose of this thesis is to provide a comprehensible and universal answer to both topics. The instrument chosen for risk analysis is a simple sensitivity analysis. Based on this, on the one hand the effects of variations of individual input parameters on the residual are investigated quantitatively by means of case studies of a valuation example. On the other hand, the hypothesis of the sensitivity of a residual value is abstracted depending on its size ratio to each of the variables and investigated by a series of mathematical calculations. Through abstraction the general validity of this scientific work for all residual value methods is demonstrated and comprehensibly presented. The results of this quantitative research are subsequently tested by several random samples to fulfill the quality requirements of scientific work, in particular with regard to its validity and reliability. The two answers to the questions investigated on the one hand enable the recipient of a real estate valuation to critically question the results of residual valuations and, on the other hand, indicate to the appraiser when the input data have to be exactly derived from the market to represent a valid valuation result. Supplementing the literature search in the relevant national and international specialized media and the quantitative empirical research of this thesis, questionnaires were sent to the member organizations of TEGoVA. The Europe-wide survey of real estate experts has clearly shown that appraisers have a diverging understanding of the sensitivity, subsidiarity and applicability of the Residual Method. This thesis therefore forms the basis for further research and shows the urgency of an international harmonization of the Residual Value Method in real estate valuation.