Differences might include age, lot size, location, view, amenities and market conditions. If the subject property has a fireplace and one of the comparables does not, the subject property might get credit for having it, which would increase its relative value. Appraisers are concerned with the big picture. They want to see how the subject property compares to others in the same neighborhood or general area. After looking at the house, viewing it in the context of its setting, and measuring its outside dimensions, the appraiser moves to the inside of the house.
Appraisers are observers of the property.
The appraiser will take lots of notes about the house, its style and its features because they are needed in comparing the subject property to the comps. Functional obsolescence might be an outdated traffic pattern, rooms that would be considered too small by today's standards or a lack of closet space. The appraiser may take photos or make sketches of the property, its location and its rooms. The appraiser will measure the external dimensions of the house and any attachments, such as a garage, porches or an apartment. They may measure each room in the house.