Why do two valuations of the same house disagree?
Two valuations of the same house disagree because four separate decisions sit behind every valuation, and reasonable people make them differently. Which sales to include, which to leave out, how to price the differences between those homes and yours, and how much weight to give the most recent movement in the market. Neither number has to be wrong for them to be tens of thousands apart.
That is an uncomfortable answer, because the figure itself never looks uncertain. It arrives to the dollar, on a clean page, and gives no sign of how much judgment went into producing it.
The four decisions
Which sales count. A valuation is built from comparable sales, and somebody has to choose them. How far away is still the same market. How far back is still current. How different can a house be before it stops being a useful guide. A sale one street over in a different school catchment might belong in one set and not in another, and both choices can be defended.
Which sales are set aside. This is the decision that moves numbers most and gets explained least. A sale between family members, a property sold as-is after a death, a transaction where the buyer had an unusual reason to pay more. Leaving those in drags the number one way. Taking them out has to be justified. A good valuation names the ones it excluded and says why.
How the differences get priced. No two houses match exactly. One comparable has an extra bathroom, another is four hundred square feet larger, a third was renovated two years ago. Every one of those differences is converted into a dollar figure, and there is no universal table for that conversion. Different methods produce different adjustments on the same pair of houses.
How much recent movement matters. A sale from eight months ago happened under different conditions than one from last month. How heavily to discount the older one is a judgment, and it is the judgment that varies most between one valuation and another.
Why the number never looks uncertain
An automated estimate reports a figure to the dollar, often with a confidence label beside it. That label is usually computed from how closely the selected sales agree with each other, rather than from how complete the underlying records are. Tight agreement between incomplete inputs produces a reassuring score.
So the presentation of a valuation carries almost no information about the quality of the work behind it. A careful analysis and a careless one look identical on the page.
What to do with two numbers that disagree
Do not average them. The gap is information, and averaging discards it.
Ask each valuation which sales it used. If both used the same sales and still landed apart, the difference is in how the adjustments were made, and that is usually a smaller gap than it first appears. If they used different sales, that is the real disagreement, and the question becomes which set better describes the buyers who would seriously consider your house.
The honest position is that a valuation is a supported opinion, not a measurement. Two supported opinions can differ and both remain defensible. What separates a strong one from a weak one is whether it shows you the sales, the exclusions and the reasoning, so that you can test it rather than take it on trust. For more on why the width of a valuation range is itself a finding, see what it means when a valuation gives you a range, and for the same question at a technical level, why home value tools disagree.
Frequently asked questions
Why is my home worth different amounts on different websites?
Because each site picks a different set of comparable sales and weighs them differently. One may include a sale half a mile away that another excludes, one may treat a six month old sale as current while another discounts it, and they price differences between homes using different assumptions. The homes are the same. The four decisions behind the number are not.
Which home valuation is the most accurate?
The one whose working you can see. Accuracy is not something you can judge from the figure itself, because every estimate is presented with the same confidence. What you can judge is which sales were used, which were left out, and why. A valuation that shows you those choices can be checked. One that shows only a number cannot.
Should I get more than one valuation?
Yes, and the point is not to average them. Two valuations that disagree are telling you where the evidence is thin. Ask each one which sales it used. Where they picked the same sales and still landed apart, the difference is in the adjustments. Where they picked different sales, that is the real disagreement and it is the one worth resolving.
One limit worth stating plainly: agreement between two valuations is not proof either is right. Two analyses drawing on the same thin set of sales will agree with each other and can still be some way from what the house will sell for.
This article is general information, not financial advice. For a specific home, have a local agent run a comparative market analysis on current comparable sales.
The Independent Agent
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Written by Nikola G.