Radio age research, manufacturing, communications, broadcasting, television (1941)

Decoder machine speedily translates data from Audi- meters to provide ratings of television shows. distributed in some 700 homes which have been care- fully selected to represent a cross-section of all television homes in the United States. Thus Nielsen can take the findings within this sample and project them to produce the size of audience in terms of millions of homes. As an example, Nielsen reported a rating figure of 38.9 for the NBC Spectacular "Tonight At 8:30". This meant that 38.9 per cent of the potential television audience, or 10,795,000 homes, were tuned to the pro- gram. This is the figure which NBC and other networks and our clients and agencies use to determine audience size. The Audimeter records its findings on film which is sent regularly to the Nielsen offices in Chicago for analysis. At the Nielsen "Fact Factory," as it is known, these minute-by-minute recordings are analyzed ex- haustively to produce whatever data is needed. Each Nielsen report covers two weeks, thus giving the figures greater stability and minimizing the unusual effects of weather, special broadcasts and statistical chance and other unpredictables which can affect sample measurements. Two reports are published every month, so that virtually every week of the year is measured by Nielsen. American Research Bureau The American Research Bureau uses another method, the diary sample. With this technique, sample house- holds are given forms with a week's programming divided into 15-minute periods. Viewers are asked to check off the periods which they have tuned in to during the seven days. The ARB diary is a national sample and, like the Nielsen survey, is projectable to produce percentages in the number of homes reached. ARB also measures viewers per set and thus can produce audience figures in millions of viewers. However, the ARB figures are on an average-quarter-hour basis rather than a total- homes-reached basis and they cover only the first week of each month. On the other hand, they include sustain- ing programs which generally are not covered by Nielsen. Trendex Trendex, the third service, uses the telephone co- incidental survey method. Trendex researchers pick names from the telephone book and call the homes to ask what program their set is tuned to. This produces an average-minute rating, which is the percentage of homes viewing during an average minute of the pro- gram. The Trendex ratings, however, are developed from a sample in only ten cities where at least three television stations are in operation. Nine of these ten cities are in the Eastern Time Zone and one, Chicago, is in the Central Time Zone. This survey, therefore, cannot be called a national measurement nor can it possibly meas- ure audience size as do Nielsen and ARB studies. Trendex produces rating percentages which are primarily valuable as quick checks on program performance in this limited number of ten cities. Trendex ratings are more volatile than the figures of other ratings services. This results not only from the sample size and measurement technique but from the limited geographical coverage which accounts for about 21 per cent of the television sets in the country and from the effect of such local program competition, such as baseball in New York and Chicago. Trendex, like ARB, surveys only in the first week of each month and thus reflects to a maximum degree radical fluctuations created by weather conditions, holi- days, special events and unusual promotion or publicity efforts. Difference in Measurements So what causes all the confusion? It arises from the basic fact that the different services are using different methods to measure different things. There is undue emphasis on the quick rating for the simple reason that its immediacy makes it more interesting. It is only human that we talk and read most about the overnight rating which may come out the morning after a new show. The confusion arises later when more meaningful ratings, measuring the total audience, become available. RADIO AGE 23