Calculating ARV for a flip

[Katie Cool]

When figuring the ARV for a flip, I'm curious how others get there. I have been going off the average cost per sf of sold, updated houses, within a mile, with similar sf, baths, br and lot size, and sold within the past 3 mos. I do not consider REO's and SS since they are always lower. Then I multiply the average $/sf by the sf of the house I'm considering to get the ARV.

I know of other investors who also take the average $/sf of pending sales and active sales into account.

How do YOU figure out your ARV? Thanks.