What is an appraisal?   

An appraisal is a thought process leading to an opinion of value. This opinion or estimate is arrived at through a formal process that typically uses the three ''common approaches to value''. They are the Cost Approach - which is what it would cost to replace the improvements, less physical deterioration and other factors, plus the land value. There is the Sales Comparison Approach - which involves making a comparison to other similar, nearby properties which have recently sold. The Sales Comparison Approach is normally the most accurate and best indicator of value for a residential property. The third approach is the Income Approach, which is of most importance in appraising income producing properties  it involves estimating what an investor would pay based on the income produced by the property.