Selection Is the Argument
Every comp case begins with a choice about which sales belong. Time is the first filter, and the freshest closings carry the most weight, with anything past a year treated as history rather than evidence. Product is the second filter, and it is where most bad comps are born. A house and a condominium are different products, dirt and water are different products, and a renovated house argues against an original one only after money bridges the gap. We keep the segments apart because blending them produces a number that describes nothing, a problem we showed at market scale in The Hidden Market.
Adjustments Are Judgment
Once the set is chosen, every difference between your home and the comp becomes a line item: the extra bedroom, the dock, the renovation year. No line item carries a label with its worth. Each is an estimate, and small estimates compound. Shift three adjustments modestly and the same comp set supports two defensible values a full tier apart. That is not corruption, it is the nature of the exercise. The question to ask about any valuation is not whether the comps are real but why these comps and why these adjustments. We walked through the appraisal version of this in When the Appraiser Is Wrong.
Building the Better Case
The strongest comp case in this county sees sales the portals never show. In some enclaves roughly four in ten closings never touch the MLS, moving instead by deed between private parties. A valuation built only on listed sales misses that entire layer of evidence, and in the off market neighborhoods the layer is the market. The second edge is the pending file. Closed sales describe the past, while contracts signed last week describe the price buyers accept today, a gap that matters whenever the market is moving, as it is this season. The third edge is candor about weakness. A case that concedes the bad comp and explains it survives negotiation, while a case built on cherry picking collapses at the first counter. That is the standard we hold our own valuations to, and the standard worth demanding from anyone who hands you a number.
Bottom Line
A comp is evidence, a comp set is an argument, and the number at the end is a position someone chose to defend. The buyers and sellers who do best treat every valuation as a case to be examined: which sales were admitted, which were excluded, and what each adjustment assumes. The questions are short, and they change outcomes.
For anyone handed a number this season: ask why these comps and not the three that were left out. The answer tells you whether you are holding analysis or advocacy.
The share of sales that never reach the MLS varies by community. Our deed research in the county's off market enclaves found roughly four in ten closings moving outside the listed market in the most private communities, detailed in The Hidden Market. Figures are orientation for how evidence is assembled, not a valuation of any specific property.
Appraisal practice varies by assignment. The comp counts and weighting described reflect common residential practice in this market.
Palm Beach County deed records and our own closed file research.
Our published market studies, linked above.
