A real estate broker's formal opinion of likely value, based on comps. Known as a CMA, this can be used by both buyers and sellers. When prepared for a buyer, the broker should focus only on actually closed listings. Until a sale closes, the actual price is not known.
For sellers, though, a CMA should look at houses on the market as well, both those active and those pending and under contract. Why? Because a seller wants to know the competition, as well as what is likely "fair market value."