What many people don't understand is that assessing property depends on many factors: who needs the assessment (is it a bank making a loan or modifying one, which bank it is, is it a potential seller, or is it a potential buyer) and the experience, familiarity of the local area, the understanding of the 'market' (are sales going up or down), and the research of the individual making the assessment. The property itself will also be a factor and certain things may not be easily quantified by an assessor such as views, a home's feng shui (even if you don't believe in that sort of thing, many of the principles make sense), any unusual features, etc. so it is possible that one person may ascribe more value to a home than another. Basically, you could get ten different assessments by ten different assessors. A CMA (Comparative Market Analysis) is usually a good place to start for most people. It is usually done for free by your agent and it will include a list of comparable properties that have sold recently (potential sellers, without an agent that they trust, may want to interview several agents but should be wary of agents that come in extra high in value because they could just be trying to 'buy' the listing agreement, or too low in their assessments).