How we think about comparables

The set is the argument

Two analysts can apply identical methodology to the same property and reach materially different conclusions, purely on which comparables they selected. The methodology is rarely where the disagreement lives. The set is.

This is why an unexplained comp set is close to useless for review. Knowing that a property was valued against six others does not tell you anything unless you also know which six, and why those rather than the obvious alternatives.

Defensibility over precision

A comp set that can be defended in a room is worth more than one that is marginally more precise but cannot be explained. The question a committee asks is not whether the number is right to the dollar. It is whether the reasoning survives contact with someone who disagrees.

Practically, that means recording why a comp was excluded as carefully as why one was included. Exclusions are where selection bias enters, and they are almost never written down.