How do Television Networks know TV viewers don’t cheat during the Nielsen ratings?

Nielsen media research, the company responsible for compiling information on America’s television viewing habits, employs a device called the Nielsen People Meter to get its figures.

The electronic meter, which is about the size and shape of a small cigar box, is attached to each of a sample family’s television sets, and whenever a set is turned on, the meter automatically records the time and the channel. The meter also documents channel switches and the time at which the set is turned off.

Since the meter communicates directly with the television set, going over the head of the fallible viewer, the possibility for cheating is all but eliminated. The machine remembers what people watched until Nielsen technicians collect the data, and if someone was to detach the machine from the television set, it would remember that, too.

Nielsen maintains a field of four thousand sample viewing households, a demographically representative sample of the entire country, and applies the information it receives from them to the country as a whole.

If 15 percent of Nielsen sample viewers tune in to a program, the company assumes that 15 percent of the national television audience tuned in along with them; the program would then be assigned a rating of 15. Since 92.1 million U.S. households have televisions, a rating of 15 translates into 13.8 million households. The math works like this: 15 percent (rating) x 92.1 (U.S. households with television sets) = 13.8 million (number of households tuned in).

In order to obtain viewer profiles, the Nielsen People Meter is equipped with a number of personal viewer buttons, one for each sample household member. When a sample viewer turns on the TV set he is supposed to identify himself to the meter by punching his button.

Button number one, for example, would belong to Bob, a thirty-five-year-old father, while button number two would belong to Shirley, Bob’s thirty-year-old wife, and button number three would belong to their five-year-old daughter, Susie. The viewer identification buttons do allow for the possibility of deception, as there is nothing to prevent little Susie from punching Bob’s button every time she turns on Sesame Street. Even so, while such deception might throw off the demographic breakdown slightly, it would not affect a show’s rating.

Another source of error arises when someone turns on the set and then goes into another room, say, to prepare dinner; since the show is on, it gains rating points even though no one is watching it.

If a sample viewer is really intent on disrupting the ratings, he could secretly buy an extra TV for private use, all the while keeping the metered set tuned in to talk shows and late-night movies. Admittedly, such behavior, if it exists at all, is extreme, and Nielsen doesn’t waste time worrying about infiltration by the odd crank.

Nielsen collects the information stored in its People Meters nightly by means of a direct phone line to each box. The company usually does this around two o’clock in the morning when everyone is asleep.

The four thousand sample households, selected randomly from a pool maintained by Nielsen, remain pretty much constant. Changes occur when the members move and leave the meter behind, or when a household tires of participating in television research and asks Nielsen to come remove the meters.