Comparable sales: how a protest case actually gets built

Texas appraisal districts value residential property largely through mass appraisal: statistical models built from recent sales of similar homes, applied across a whole neighborhood at once. It's efficient at scale, and it's also where most protestable errors come from.

What makes a sale "comparable"

Square footage, age, condition, lot size, and proximity all matter, but so does timing. A sale from 18 months ago in a fast-moving market tells a different story than one from last quarter.

Where the model tends to miss

• Condition differences a drive-by appraisal can't see, foundation issues, deferred maintenance, an outdated interior
• A comparable that's technically nearby but functionally a different type of home
• Square footage or room counts pulled from outdated permit records

A strong protest case doesn't argue the value is "too high" in general. It shows, with specific comparable sales and documentation, why the model's inputs don't match the actual home.

This is the part of the process Andy automates first: pulling recent, truly comparable sales near your address before a case is ever filed.