The short answer is, not all homes are created equal. When looking for comps, the Valuation Report, the real estate agent, the appraiser all have to use the current sales data that is available to them. If an exact floor plan to the subject property has recently sold, that is generally considered a good comp. If that same property (exactly the same) sold three years ago, it’s considered too old to be a good comp. Appraisers, CMA’s and Valuations go through a logical process of making adjustments for difference is between properties. If a four bedroom, two bath home, with 2000 square feet is being compared to a five bedroom three bath home, the various valuation approaches will make an adjustment in value in an effort to make that sale “comparable” to the subject property. In that manner, they can judge value based on the similarities and differences of each property.