Assessed value per square foot: the number that makes comparisons possible
Raw assessments cannot be compared. Rates can.
Two houses assessed $95,000 and $120,000 tell you nothing until you know their sizes. Divide by square footage and the comparison becomes real.
Which square footage
For a building-uniformity argument, assessed total ÷ building square feet. For a land argument, assessed land ÷ lot square feet — and never assessed total ÷ lot square feet, which compares a house plus land against bare ground and manufactures an over-assessment out of nothing.
Worked example
Your house: $120,000 assessed, 2,000 sq ft → $60.00 per sq ft. Neighbour: $95,000 assessed, 1,900 sq ft → $50.00. You are assessed 20% more per square foot for a property the record describes almost identically. That is a specific, checkable claim.
What it does not adjust for
Condition, finish, updates, views, corner lots. A rate comparison is a starting point that identifies where to look, not a conclusion. If the house assessed less has a failing roof and yours has a new kitchen, the gap may be perfectly defensible.
Use the median, not the average
One enormous or one exempt parcel drags an average badly. The median is what mass appraisal itself tends to target and what a board will recognise.