An Investigation Into the Use of “Hybrid” Adjustment Techniques in the Application of the Sales Comparison Method in Residential Valuation

The sales comparison is the most common and universally accepted method in valuation. Although the theoretical entry point of the method is the same across most continents, its application in practice is varied and often determined by local circumstances. This often necessitates the modification of the method. For instance, while Zambian valuation practice uses this method in residential valuation, its application goes beyond the basic valuation model, incorporating a less known technique called the “reduced floor area (RFA)” technique. The RFA technique is a form of relative importance (weight) concept which assesses ancillary buildings on site relative to the main use; for residential properties this is the main house on site. Despite its obscurity in valuation literature, practitioners find its use acceptable within the dictates of local circumstances. Nonetheless, the lack of documentation means knowledge on the technique is transmitted verbally from senior valuers to graduates, and its application is not consistent across the profession, contributing to variances in the assessed values. This necessitates detailed scrutiny of the technique. Data for the study was collected from the Valuation Surveyors Registration Board (VSRB), a statutory body responsible for licensing valuers and regulating valuation practice. This is the first time the RFA technique is being discussed in a scholarly article.