Understanding MLS Data Reconciliation for Accurate Appraisals
MLS records and county data do not always agree. When square footage, lot size, or room counts conflict, which source should you trust? A practical decision framework.
January 20, 2026
Anyone who has pulled comps knows the frustration: the MLS listing says one square footage, the county assessor says another, and a third source says something different again. Reconciling those disagreements is part of the appraiser’s job, and how you do it affects the credibility of the report.
Why the sources disagree
Different sources are built for different purposes. MLS data is entered by agents to market a property and is not always independently verified. County records are maintained for assessment and may lag behind renovations or reflect different measurement conventions. Neither is automatically "right" — they are answering slightly different questions.
A practical decision framework
When sources conflict, start by understanding what each one is actually measuring and when it was last updated. Prefer the source that is most directly tied to a verifiable measurement, and where you can, confirm against your own observations from the inspection.
When you cannot fully resolve a discrepancy, document it. A short note explaining which source you relied on and why is far more defensible than silently picking a number.
The takeaway
Data reconciliation is judgment, not lookup. The goal is not to find a single perfect source but to make a reasoned, documented choice that another professional could follow and agree was sound.