A "CMA" otherwise known as a comparative market analysis, is used to help sellers determine a fair market value of their property or help buyers that are considering buying a home and want to know what a fair price would be.
CMA is similar, but not the same as an appraisal. It is the opinion of the value of your home based off the sales in the area of the subject property. We take the subject property stats and enter them into our database and pull up other properties with in the area, with similar characteristics. We then take the price that the comparative properties sold for minus concessions to get an actual value of what some one is willing to spend on a home like the subject property.
Concessions are items that were included with the sale of the home. If a property sold for $220000 but had $5000 in concessions. the house really sold for $215000 and the seller agreed to pay towards something towards closing costs, or carpet.
Often times people refer to other real estate web pages like Zillow to determine the value of their property. Many of the sites that offer this information tend to have old information some up to many years old. This gives a false value of your home. They also don't report concessions paid by the seller.
I have noticed that most people really are not interested in talking with a Realtor. There are many reasons for this. They don't want to pay a commission. They just don't want to bother with a sales person or they have had a bad experience in the past that has put a bad taste in their mouth.
Unfortunately there are many agents and brokers out there just for the money. If you do your due diligence there are many Realtor's out there that have a lot of knowledge and can do a proper CMA and get you more money for your house than you thought. Every Realtor I know, me included, will do a comparative market analysis on your home for free.