Advertising makes the world go round, or at least, the world of mass media. Advertisers pay to have their products and services highlighted in front of viewers and listeners, and the fees they pay vary according to how large of an audience they reach. Media marketers use ratings and shares as key measures of the size of an audience watching television, listening to radio or otherwise using mass media.
A rating is a measure of the percentage of households with a media device that is using the device to watch or listen to a particular program. For example, if 1,000 homes have televisions and 100 of those homes have the TV on and tuned to a specific show, then that show's rating is 100 divided by 1,000, or 10 percent.
A share is similar to a rating but is limited to households with the media device, such as a television or radio, turned on. For example, if 1,000 homes have radios, 500 of those homes have the radios on and 100 homes are listening to a particular show, then the show's share is 100 divided by 500, or 20 percent. In contrast, the show's rating is 10 percent.
Nielsen is the most well-known of the media rating companies. Advertisers and programmers pay careful attention to Nielsen ratings and shares data, and negotiate the price of advertising based on the data. Nielsen provides data in a variety of areas, including broadcast and cable television, Internet traffic and mobile phone use.
Arbitron Inc. is the largest provider of audience statistics for the radio industry. The company provides share and ranking information along with detailed breakouts of radio audiences by demographic features such as age, ethnicity, gender and income.
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