Overview
Cable TV ratings are compiled mainly though audience tracking data collected by Nielsen Media Research, a company which has been collecting marketing and advertising data from consumers since the 1920s, and added radio and TV research when those forms of broadcasting took hold in the United States. The cable networks contract out with Nielsen, currently the only company with the resources to provide nationwide viewing data, to obtain information about how many and what types of people are watching their programs, as well as other demographic factors pertaining to their viewers.
Sampling
The Nielsen company uses random sampling to get a wide cross-section of people grouped in different age, ethnic, geographic and other demographic categories. This helps create a more accurate estimate of the larger number of people across the greater population watching a program when selecting candidates to participate in the ratings surveys.
Audience Measuring
Nielsen has two main ways of collecting information from TV viewers. The first is through meters connected to TVs in the homes of people who are selected and agree to take part. The meters record minute-by-minute data on which programs and channels are being watched at any given time in the household, and by which members of that household. That information is relayed back to Nielsen each night via modem, compiled and sent to cable networks--as well as broadcast networks and affiliates--each morning for the overnight ratings. The meters also track which programs are recorded with DVRs and watched up to a week later. Nielsen has made a deal with Charter Communications to receive data directly from the cable box/DVRs, and is looking to do the same with other cable providers as well, though that can only track what is being watched and not who is watching. In addition, during the four "sweeps" months--November, February, May and July--Nielsen selects additional people to keep diaries of their TV viewing habits for one week. These diaries are mailed back and added into the ratings.
Using the Data
Cable networks analyze the ratings points and the demographic makeup of their viewership and use the information to set the advertising rates they charge sponsors during specific programs and at given time periods. The numbers are also used to gauge the popularity of their shows to help them decide which shows to keep airing and where the strengths and weaknesses of their schedules are.
Tags: being watched, given time, other demographic, which programs