Comment Re:PHB Response (Score 1) 115
Nielsen allows stations to "retitle" programs if there is something about the program beyond the station's control that affects viewership. As an example, a sporting event runs long, and the newscast runs an hour and a half late, and viewership drops substantially. That would impact the average ratings of the newscast in its normal time slot when every other station in the market is running its news at the normal time, so the station is right to exclude that aberration from the running average. Think of it as "The Eleven O'Clock News: Special Edition" or something.
Even with retitling programs that fall in this category, Nielsen still reports the ratings, so ad buyers can evaluate for themselves. There are clients who will only buy time in newscasts, and only in newscasts that run on time. They don't want to spend big bucks if the show is an hour late.
As for actual program ratings, Nielsen relies mainly on portable people meters (PPMs) that record viewing in real time by listening to codes embedded in the audio. They just rolled out a new, finer-grained coding system (critical band encoding technology) which delivers better code reading ability in noisy or difficult environments. So there is actually no escaping Nielsen's viewer/listenership gathering mechanism, at least in the larger (top 50) markets.