The Bias Actually Happening When a Seller Quotes Their Zestimate
A seller who opens a call with "Zillow says my house is worth $X" is not being stubborn or uninformed on purpose. They are exhibiting anchoring, a well-documented cognitive bias where the first number a person encounters becomes the reference point every later piece of information gets judged against, even when that first number was never especially reliable to begin with. Arguing directly that the number is wrong rarely moves anyone, because the argument is aimed at the number, not at the bias holding it in place.
Why the Number a Seller Sees Is the Least Reliable Version Zillow Publishes
Here is the detail that makes this specific anchor especially fragile: Zillow’s own published nationwide median error rate runs approximately 1.9% for on-market, currently listed homes, but jumps to 7.06% to 7.49% for off-market homes. An active listing gives Zillow’s model a human-set asking price to anchor to, which is exactly what makes the on-market figure tighter. A seller who hasn’t listed yet, the exact seller on a cold call, is being quoted the off-market version, the one Zillow’s own data says is least accurate, and quoting it back as gospel before ever testing the market.
Want this handled for you?
Our Human + AI SDR team cold calls your market, qualifies sellers against your criteria, and hands you the appointment. You pay for qualified leads, not hours.
Book a Real Estate Fit CallThe 1987 Study That Shows Even Agents Can’t Just Ignore an Anchor
The foundational research here is Northcraft and Neale’s 1987 study, "Experts, Amateurs, and Real Estate: An Anchoring-and-Adjustment Perspective on Property Pricing Decisions." Both real estate agents and student amateurs toured an actual house for sale, given an identical information packet except for one manipulated detail, the stated listing price. The result: value estimates across every measure used were significantly anchored to that manipulated listing price, for professional agents just as much as amateurs, even though the agents believed they were pricing the house independently of it. If trained professionals cannot fully escape an anchor they know is arbitrary, a seller with no pricing training at all is not going to escape one just because an investor tells them the number is wrong.
Resetting the Conversation Around ARV Without Calling the Seller Wrong
The 1987 study points to the actual fix: since a direct correction does not dislodge an anchor, the more effective move is introducing a new, competing anchor grounded in real evidence rather than attacking the old one head-on. Walking a seller through actual after-repair-value comps, what similar houses in real condition on the same street have actually sold for, gives the seller a second reference point to weigh against the Zestimate instead of a flat argument that their number is simply wrong. The goal is not to win the argument about accuracy; it is to give the seller’s own anchoring instinct something more solid to latch onto.
Why the Reset Has to Come From the Seller, Not From You
A seller who arrives at a lower number on their own, by looking at the same comps and repair costs an investor is looking at, holds that number very differently than a seller who is simply told to accept it. Getting there takes patience and the ability to walk through real evidence live on a call, not a rehearsed rebuttal to "but Zillow said."
That is the kind of conversation VA Horizon’s Human + AI SDR team is trained to hold, walking a seller through the comps that actually matter rather than arguing with the number stuck in their head, so the appointment reaching your calendar already has a seller who has started resetting their own expectations.
Sources
The external data in this article draws on the sources below. Figures described in the text as estimates or industry triangulations are directional and are not attributed to a single dataset.
- Zillow Zestimate accuracy data, corroborated via multiple real estate education sources citing Zillow’s methodology
- Northcraft, G.B. & Neale, M.A. (1987), "Experts, Amateurs, and Real Estate: An Anchoring-and-Adjustment Perspective on Property Pricing Decisions"