How are"Recently Sold" prices determined, other than from true sales?

Recently sold is going to include the kitchen sink of data - every sale including builder sales, re-sales, short sales, foreclosures, investment properties, etc.

What you have to be aware of (for all methods of calculation) is the source of the data.  Zillow, as far as I know, relies completely on tax data.  When looking for national data, it is the only source likely to have any consistency.

Listing services have all sales that were published through them, but they are not going to contain For Sale By Owner or a handful of other items.

The larger challenge is the accuracy of the data - regardless of source.  The government records - particularly in Atlanta - can be way off when you look at things like square footage.  For example - many homes in Atlanta have been expanded over the years, but the records are almost never updated.

With the old data, you may have a 4,000 square foot home listed in the tax records as 2,300 square feet.  This creates an erroneous price per square foot, and makes the data much more challenging to use.

Similarly, a home may have a basement room that is "listed" by an agent as a bedroom.  It may be decorated as a bedroom, but without a window and a closet, it doesn't qualify.

In order to arrive at an accurate price for your home, a number of factors come into play:  Recent sales (preferably from multiple sources to cross check and validate data), types of sales - re-sales may need to be treated differently than builder sales, foreclosures and short sales should definitely come into play, condition of the comparable properties, age and effective age, location (even within a neighborhood), school districts, property tax implications, and current properties on the market (and their type / condition), etc.

It takes no time to generate a generic report, but it is rarely going to be accurate.  Real property valuation takes time, research, knowledge, and effort.

Zillow "recently sold" information comes from the government offices in each office where this information is recorded.   In some places it appears in two or three weeks, in other areas it has been as long as six months.

It does not distinguish houses that are owner occupied vs investment properties.

Your local Realtor© will have full access to the "recently sold" in your area.

Other sources are available.

Good Luck!

James Callas - Realtor©