How do the tv networks know how many people watch what?
Basically, Neilsen Media picks a sample group to study that is proportionally the same make-up as America itself. Here’s how they explain it: Nielsen TV families are a cross-section of households from all over the United States. We carefully draw our samples in a way that offers every American household with a television an equal chance of being selected. Sample design, selection, and maintenance for both the national and local market samples are the responsibility of highly-skilled statisticians — Nielsen’s guardians of sample quality. They stay abreast of new sampling methods developed by survey organizations, the U.S. Census Bureau, and other government agencies. Our samples include homes from all 50 states, from cities to towns, from suburbs to rural areas. We have homeowners and apartment dwellers — some with children and some without — across a broad range of demographic categories. We include people of all ages, income groups, geographic areas, ethnicities and educational levels
