What is "unequal appraisal" and how do I argue it?

Unequal appraisal is a uniformity argument: regardless of whether your assessment is above market value, it is unfair if it's higher than the assessments of comparable properties. This is the wedge that wins in rising markets, where "my home is worth less than the assessment" claims often fail but "I'm taxed more than identical neighbors" still succeeds.

Two distinct arguments. A standard valuation appeal says your assessment exceeds market value. An unequal-appraisal appeal says — even if the market-value question is a wash — your assessment is out of line with comparable assessments. You can run either or both; uniformity is frequently the stronger one when home prices are climbing.

How to build it: 1. Identify a set of true comparables — several nearby homes similar in size, age, style, and condition. One lower neighbor isn't enough; boards look at a group. 2. Pull their assessed values from public records and adjust for real differences (size, lot, condition) so the comparison is apples-to-apples. 3. Show your assessment sits above the median of that adjusted set. The remedy is typically to bring your value down to the median or the equitable level.

Where it's codified strongest:

• Texas — the equal-and-uniform protest under Tex. Tax Code §41.43(b)(3): your appraisal is excessive if it exceeds the median appraised value of a reasonable number of comparable properties appropriately adjusted. The Texas Comptroller lists unequal appraisal as a protest ground.
• New Jersey — the Chapter 123 ratio test (N.J.S.A. 54:3-22): if your assessment-to-true-value ratio falls outside the municipality's common level range (±15% of the average ratio), the county board revises it toward the average ratio.
• Illinois (Cook County) — a "lack of uniformity" appeal where the Cook County Assessor compares the assessed values of similar nearby homes (you may attach up to six comparable PINs), with residential property at a 10% level of assessment.

Why it converts: it's objective (assessment records, not market opinion), it's gatekept by consultants who treat it as a specialty, and it wins where ordinary value arguments lose.