The television research giant has attached the famous black boxes to a random sample of TV sets in the 30 largest markets, giving those stations and their advertisers a fix on the size of the TV audience 365 days a year. For the rest of the cities across America, the ratings firm sends out diaries to homes selected at random. Willing TV families keep the diaries for one week, writing down who is watching what broadcast or cable channel. The diaries are mailed back to Nielsen's processing center in Dunedin, Florida. What comes back four times a year is a printed report on the size of TV audiences, defined primarily by the age and the sex of the viewers.
Socioeconomic information is very limited, and there are no comparisons to other media.
For the local advertiser, combining TV ratings with information from qualitative services like Scarborough or Media Audit gives you the best picture of your customers and the media they use most often. However, all those terms can be translated into simple numbers like newspaper circulation figures. Don't bother to reach for your calculator. Ask the TV sales rep to do the conversions for you. Like television, radio stations must subscribe to a ratings service to find out how big their audiences are.