How to get accurate comps with huge swings/ranking factors?

[Arielle O.]

In my analysis of comps, it is quite challenging to get a good feel (maybe due to COVID) as there are huge swings in what comps are going for ($600/month swings), as well as the fact that there aren't that many comps with same number of bedrooms and bathrooms. The property I'm looking at also has below-grade bedrooms which is a "negative" but is newer construction for the area, which is a "positive" considering most other houses were built in early 1900s -- how do you find accurate comps? Specifically, how much do you cut off average rent prices due to basement bedrooms? How much do you "add" for new construction (built last 5 yrs)?