Comparable sales, or comps, are recently sold houses similar in size, condition, age and location to the one being priced or appraised. Appraisers and agents use them to support a value, and the fewer differences between the comps and the subject house, the more the comparison is worth. A house with no recent, similar sales nearby is harder to price with confidence.
Why it matters
The comps behind a number are what let you check whether a price, an offer or an appraisal actually holds up.