Is there a formula to justify the difference between q3 construction home and a superior q2 construction home in the grid. My supervisor does not know and never does this. I have been finding it necessary within our area market.
1. Make sure you have a firm understanding of the differences between a Q2 and Q3 home. Consult cost guides and UAD definitions as needed. Please note I did not end the sentence by saying "in your market". Because a Q2 home is Q2 in Beverly Hills, Nome, AK, South Beach, and Ottumwa, Iowa. The difference in prices of those homes is driven by location, cost to construct, and other factors, but Q2 is Q2.
2. Once you are sure you can properly identify and label Q2 vs Q3 homes, then a good starting point is identical location and GLA homes that are Q2 vs Q3. Eliminate as much of the differences as you can, so that only quality is different--as much as possible anyway.
3. Not to pile on, but a supervisor/mentor really ought to be able to better assist you in this. If they are deficient in this, which honestly is pretty basic, one has to wonder in what other items they are deficient. They should be asking the question of their peers, IMHO.
4. Like condition, quality ratings are meant to be holistic. There is a difference in the quality of a home that is borderline Q2/Q3, and one that is Q3/Q4. I am not afraid to get more granular in my quality ratings--but understand the more granular you get, the more subjective things become, because it is a lot harder to derive and support adjustments for smaller elements of quality, like countertop type, flooring quality, ceiling height, trim level, etc.
5. Like TMG mentioned, if at all possible, stay with Q3 comps. Even if it means going back in time or farther out in distance. Quality/Condition adjustments are sort of the last resort, at least to me.
Good luck!