For example, an evaluator valuing a suburban property located in a developed region may miss out steps in the normative evaluation process (such as high and low land value opinion and market analysis) and advance to the sales comparison approach. In the event that unusual market signs are detected in the data, evaluators may revisit the prior evaluation phase and consider re-investigating existing market trends. From their education and experience, they develop practical production rules that simplify the valuation predicament.Firms lack standard forms of expressions force evaluators to explain to the client the possibility of property fluctuation based on market conditions. This calls for valuation bias that may be caused by inconsistencies in either overvaluing or undervaluing properties (Joslin 2005, pp. 276). The expression of uncertainty in valuation is commonly used to enhance decision making by aiding users to understand the valuation basis. Therefore, most evaluators apply the clause of using estimated figures that are prone to change rather than the exact figure laying emphasis on the non-guaranteed standard of a certain figure and subject to eternal variables (French and Gabrielli 2006, pp. 15). In such circumstances, valuation biases arise from evaluators who alter and misjudge market conditions positively or negatively by overvaluing or undervaluing properties.Behavioral research into real estate valuation process also identify the interaction of the complex task environment (including market data such as sales information, pending sales rates and relevant market information) with the human processing system (both short-term and long-term memory) as a leading factor to increased uncertainties caused by information processing that differs among individuals (Diaz and Hansz 2002, pp. 5).