I think new construction might be a better gage on how much price has fallen than resale price since builder are much more realistic in term of what price they can get right now. While resale price, seller might be stubborn and not sell it to the best current offer, holding out and hoping a better one will come in the future. Also, a lot of the new houses/condo tend to be much more uniform in term of content than resale, so it reduce some of the effect of upgrades in resale.
