A television programme or a commercial sent over the air, on a cable system, or direct from a satellite is available for viewing by millions of viewers. How does one know how many of those millions are actually viewing a particular programme? Unlike a newspaper or a magazine, where the publisher can count how many copies are sold, there is no direct way to know exactly how many people are watching any given programme. Hence, indirect measuring techniques based on the statistical sampling theory, called Television Audience Measurement (TAM), are used.
Technically speaking, TAM is a specialised branch of media research, dedicated to quantifying and qualifying detailed TV audience information. In India, TAM is commonly referred to as TRP or TV Ratings Points. Generally, when used for the broadcast medium, a rating point equals 1% of the given population group.
Why do we need these ratings?
With the hundreds of crores of rupees spent annually on TV programmes and commercials, reliable TV audience information is required to evaluate and maximise the effectiveness of this investment. This has led to the ever-increasing desire by broadcasters, advertisers and advertising agencies to have accurate, consistent and detailed information about TV audiences. These ratings, if reliable and valid, become `common currency' for the market's commercial airtime. Media planners and buyers evaluate the alternative programmes offered to best achieve their advertising goals, broadcasters evaluate programmes or a station’s popularity and how much to charge advertisers for commercials during a programme or on a given channel. In those cases where the channels are funded wholly or partly by public licence, they provide accountability.
How is viewership measured?
There are many ways to measure the audiences. One is through random telephone calls (if teledensity is satisfactory). Another is by using TV diaries, booklets in which samples of viewers record their television viewing during a measurement week. However, with the increasing numbers of channels, multiple broadcasting platforms and increased numbers of TV sets and remote controls per family, electronic gadgets called people meters are used to measure audiences. The people meter, about the size of a paperback book, is placed on each TV set in the sample home. The box has buttons, and lights are assigned to each person who lives in the household (with additional buttons for guests). Each meter is capable of accurately monitoring every second, 24 hours a day, 365 days a year, what is being viewed on each TV set and by whom. The meter stores this data. The data is then periodically transmitted by means of the family's telephone line, or a dedicated cellular telephone line to a central computer for analysis. In actual practice, all the three methods are used in combination, for increasing the accuracy and for crosschecking.
The world's first people meter was installed in 1976 in 500 homes in Italy by LCM Graman, an Italian market research company. Today, AC Nielsen, AGB Group and Gallup are the three leading TAM agencies. Most of the television markets in the world have a single TAM rating. However, India till recently had two - one called TAM done by AC Nielsen and other INTAM reported by ORG-MARG. However by the end of this year, TAM and INTAM will be merged to form a consolidated industry standard.
How reliable are TRP ratings?
As with any sampling, TRP ratings could be inaccurate due to sampling errors like inadequate coverage of the TV owning population. In India, for example, TAM ratings are based on people meters installed in only 16 top cities in nine states. Also, the panel households exclude lower middle and top income bracket households, which are keen watchers of niche English channels. Then the whole system is based on the list of metered households being confidential so that their viewing habit is not unduly influenced.