The present invention is directed to a system and method comprising an expert system that provides a logical step by step decision making support system that assists and guides an actual or potential real property investor, borrower, lender, appraiser, or assessor in optimizing the components of return on a real property, investment or loan, that is embodied in a computer-implemented web-based environment. The method of the present invention contains six major phases—Qualifying, Valuation, Developing and Deciding on Alternatives, Marketing, Negotiation and Closing, and the Post Closing Phase. The system guides the user in ordering and executing the method steps within each of the six major phases. The principle advantage of this invention is that the method of the present invention is a decision support system that provides those transacting business in these market a means of optimizing their return on investment by reducing transaction cost, time, uncertainty, and risk.