raveneye

Does anybody know what the usual formulas are that appraisers use, that compute the estimated sale value of a house from past sale prices of houses in the neighborhood? (not tax assessors, but appraisers)

My understanding is that they limit themselves to less than a mile from the target house, and no farther back than one year. But I don't know the form of the equations (relating sale price to size): is it just one linear equation with slope and intercept, or two linear equations, one for smaller houses and one for larger?

Any ideas or websites out there that give a tutorial?