Picture a volunteer in Houston in 2005. She carries a pager-like gadget, about two inches long and half an inch wide, through every waking hour, then drops it into a cradle at bedtime. Overnight the device reports to Arbitron, the company that measures radio ratings, which station she listened to and which shows she watched. The New York Times Magazine described the test that April, and Engadget passed it on.
Here’s what it means in plain terms: counting an audience used to depend on people writing things down, and it now depends on machines that listen.
The old way, and why it wobbled
The method before the meters was the “Viewer’s Diary”, a paper log kept by hand. Engadget’s 2005 item described radio’s version of the problem plainly: the existing technique mainly meant getting people to keep track of what they listened to themselves. Memory is not a reliable instrument.
Nielsen, the name most Americans link to television ratings, was founded in 1923 and spent that decade in market research. In 1950 it launched its first television measurement device, derived from the audimeter that had been used for radio audiences. By 1973 the ratings were national and daily. Households taking part get a meter installed, and the sample is meant to mirror the demographics of the United States: race, age, employment, income. A university write-up in 2016 put the number of households at around 26.000, though it said the figure had grown tenfold. Counting every household would cost too much, so sampling has always been the method.
How a rating is worked out
The arithmetic is simple. Take the number of people or households watching, divide by the number who own a television, and multiply by 100%. A rating of 1.0 means one percent of television owners in that group watched the program. A share, by contrast, counts only those who have the TV on at the time, which is why advertisers lean on ratings.
Meters that listen
Arbitron’s Portable People Meter works differently from a diary. The device detects inaudible codes that stations embed in their broadcasts. Radio World reported that the first large-scale US test would take place in Philadelphia in the fourth quarter of 2000, and that Arbitron had built a low-noise “critical listening room” at its research center in Columbia, Maryland, to develop the next generation of the audio encoders. The system only works if radio and TV stations take part and encode their programming.
The practical upshot today
New viewing habits keep outrunning the meters. The arrival of the DVR forced Nielsen to report several levels of recorded viewing, and web-based TV, Hulu, smartphones and tablets added more. The 2016 write-up noted that those formats were not yet in Nielsen’s TV measurements and that ratings had been declining for years. Nielsen’s answer was a Total Audience Measurement tool meant to follow ad viewership across formats.
Sources
- Nielsen – The quandary of the ratings powerhouse – Universitat de València (iMBA blog)
- Arbitron's Portable People Meter – Engadget
- Arbitron Builds Listening Lab For Portable People Meter – Radio World
