CIMM DEFINITION: Subscriber ebb and flow – the overall loss and gain of subscribers to a service that results in a constant ebb and flow (erosion and gain) of the subscriber base.

NOTE – MSOs often recycle Set-Top Boxes  from previous customers to new ones. Thus, at least one anonymization tier must have access to both unique Set-Top Box identifier (e.g., MAC Address) and subscriber information (e.g., address) to insure that measurements from a Set-Top Box are always associated with the correct subscriber/viewer. (Source: FourthWall Media)