Yesterday, Cowen and Co. retail analyst Oliver Chen downgraded Nordstrom shares, and the stock promptly tumbled. Among the concerns he cited were declining comparable store sales at both Nordstrom’s full-line department stores and the Rack off-price division. There’s a real risk to misunderstanding what is really going on. One of the things were going to need to get used to, not only with Nordstrom but with many other brick-and-mortar-dominant retailers, is a new way of thinking about performance — and much of this has to do with letting go of comparable stores sales as a key indicator while fundamentally thinking differently about the role of physical stores. Read more at Forbes.