What makes a sale a useful comparable
A comparable sale, or comp, is a recent arm's-length sale of a home similar enough to yours that its price says something about your value. The closer the match, the more weight it carries.
- Location near your property, ideally the same neighborhood or subdivision.
- A sale date close to the valuation date the assessment is based on.
- Similar size, age, style, and lot characteristics.
- An open-market sale, not a transfer between family members or a distressed sale.
Why adjustments matter
Few comps are identical to your home, so the differences that remain are handled with adjustments. If a comp has an extra bathroom or a finished basement, its price is adjusted down to reflect what your home lacks, and vice versa.
Adjustments are what turn a rough list of sales into an estimate that actually speaks to your property. Done well, they make the comparison fair instead of cherry-picked.
Quality beats quantity
A long list of loosely related sales is weaker than three or four tightly matched comps. Boards and assessors look for relevance, not volume.
The strongest appeals stay narrow. They rely on a few sales that clearly resemble your home, with adjustments that are easy to follow.
Common mistakes with comps
Most comp problems come from reaching too far for sales that support a number rather than sales that reflect the property.
- Using sales from a different neighborhood or a noticeably different home.
- Relying on sales that are too old to reflect the valuation date.
- Ignoring adjustments and treating different homes as equal.
- Picking only the lowest sales while skipping similar higher ones.