Writing the appeal so it is decided in your favour on paper
Many appeals never get a hearing. Write as though yours will not.
Most residential appeals are decided on paper by someone working through a large stack. How you write it determines whether a good case is understood as one.
Write for the reader you actually have
They are not hostile and they are not your advocate. They are applying a standard to a file, they have many files, and they are looking for one thing: whether the evidence supports a different number.
Everything follows from that. Be brief, be specific, and make the arithmetic checkable without work.
The structure that works
One sentence on what you are asking for
"I am requesting that the improvement assessment on PIN 14-21-106-017-0000 be reduced from $34,600 to $30,194 on grounds of uniformity with comparable properties."
Number, ground, and property, before anything else.
The arithmetic, shown
Four lines: comparable median, subject floor area, supported improvement value, plus unchanged land. The reader should not have to calculate anything.
The evidence, in a table
Comparables with PIN, address, class, floor area, improvement assessed value and per-square-foot figure. Median at the bottom.
One line on why each comparable is comparable
"All four are class 203, in neighbourhood 71, built between 1952 and 1961, and between 1,690 and 1,900 square feet against the subject's 1,780." One sentence covering the set is better than a paragraph each.
How to write it
Short sentences. Numbers, not adjectives. "Assessed 18% above the median of four comparable properties" beats "grossly over-assessed".
No emotion. Frustration is legitimate and it does not help. Every sentence spent on how unfair this feels is a sentence not spent on evidence, and it signals that the evidence may be thin.
Concede what is against you. If one comparable is slightly larger, say so and note that this understates the disparity. Volunteering the weakness makes the rest more credible; being caught concealing it does the reverse.
Do not argue about things they do not control. The tax rate, the levy, school spending, or affordability. Each one costs you credibility on the question they can actually decide.
A short template
I am requesting a reduction in the improvement assessment from $34,600 to $30,194 on grounds of uniformity.
The four comparable properties in the attached table are all class 203, in neighbourhood 71, built between 1952 and 1961, with floor areas between 1,690 and 1,900 square feet against the subject's 1,780. Their improvement assessments range from $13.37 to $13.63 per square foot, with a median of $13.48. The subject is assessed at $15.96 per square foot — 18% above that median.
Applying the comparable median to the subject's 1,780 square feet supports an improvement assessment of $23,994. Adding the unchanged land assessment of $6,200 gives a total of $30,194.
Comparable 2 is 60 square feet larger than the subject, which if anything understates the disparity.
Two hundred words. It states the request, the ground, the evidence, the arithmetic and the one weakness. A reader can verify all of it in two minutes and grant it without asking a question — which is exactly what you want from a filing that will be decided without you in the room.