size of audience exposed (see exposure) to an advertisement through a particular medium. For example, the media reach of a television commercial could be millions of viewers, but the potential media reach of a local newspaper advertisement could be only hundreds of people.
Reach is difficult to measure precisely. There are usually many more readers per copy of a magazine or newspaper than the number of copies sold. Estimates go as high as 4.5 readers per copy for a particular publication. The ACNielsen Company measures the number of television sets tuned to a program based on a sample, but many more or fewer people may actually be watching. Some marketers attempt to get a true measure of reach by asking people what they remember viewing or reading.
