Does Cox collect data on what shows are watched or recorded?

I see all these ratings on how many viewers are watching a show live vs how many are DRVing it.  Are those numbers just estimates or can moders cable systems collect data on how many viewrs are watching a show?

With CBS blocking Cox Las Vegas users from watch channel 8 will that affect their ratings?  If I keep my cable tuned to another local channel even when I am not actually watching it will that lower CBS's ratings and cost them money?