How the radio ratings work
The survey offers insights about our listening habits, but it has limitations.
This blog often refers to the Australian radio ratings survey, which is conducted by GfK Australia and commissioned by Commercial Radio and Audio (CRA). So, maybe it’s worth explaining what it is and how it works.
The survey is regarded as the official measure of radio listenership across the five major metropolitan markets of Sydney, Melbourne, Brisbane, Adelaide and Perth, as well as key regional areas such as Newcastle, Canberra and the Gold Coast.
These ratings are used by broadcasters, advertisers, agencies and media planners, seeking insights into audience behaviours and preferences.
From a commercial radio perspective, they determine how much advertising money gets spent on particular stations and programs.
The key metrics are:
Share (%). This is the most quoted metric in media reports about radio ratings and indicates a station’s relative strength within a market. It shows the percentage of the total radio listening audience during a given time period that is tuned to a particular station. It’s important to note that the rating is a percentage of the total available audience, not of the entire population.
Cumulative audience (cume). This represents the number of individuals who listen to a station for at least eight minutes during a given time period. (This number gets quoted a lot, especially when the commercial stations pitch themselves to potential advertisers, but it seems to me that eight minutes spent doing something, especially if it’s over an entire week, hardly indicates a habit. If it does, then I might add “exercise” to my list of virtues.)
Time spent listening (TSL). This measures the average amount of time listeners spend with a station over a specific period. TSL is calculated by dividing the total time all listeners spend with a station by the number of unique listeners (cume).
To collect the ratings, GfK uses a hybrid methodology known as Radio 360, combining various data collection methods:
Surveys: About 50,000 surveys are conducted annually, with 80% completed online and 20% via electronic diaries. Participants are selected based on geographic distribution aligned with Australian Bureau of Statistics (ABS) figures.
Streaming data: Listening data is directly collected from radio stations’ web players, apps and server logs to capture digital streaming behaviour.
MediaWatch panel: About 2,000 survey participants use the GfK MediaWatch, a wearable device that automatically captures listening information when the wearer is in hearing range of a radio station.
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While the GfK ratings provide valuable insights, there are inherent limitations:
Exclusion of non-commercial or ABC stations: The survey does not include explicit reference to community and non-subscribing stations, so it isn’t a complete picture of listener habits or preferences.
Sampling bias: Despite efforts to match the demographic distribution of the population, certain groups may be underrepresented or overrepresented in the sample, affecting the accuracy of the results.
Self-reporting errors: Reliance on participants to accurately record their listening habits can introduce errors due to forgetfulness or misreporting. (Anecdotally, diary users have been known to “fudge” the figures after the event because who has the time or discipline to record it exactly?)
Market fluctuations: External events, such as major news stories or sporting events, can temporarily influence patterns of listening, leading to anomalies in the data.
The difference between hearing and listening. Just because a radio is playing in your vicinity doesn’t mean you are paying attention to it. And the level of attention required from the listener is different for music than it is for talk breaks and advertisements.
While the survey offers an agreed-upon and relatively robust framework for assessing radio audiences, it’s not an exact science. Acknowledging the survey’s limitations is important if you are making decisions based on that data.
Sources and related reading: GfK, Radio Today, RadioInfo, The Australian ($), CRA
For my thoughts the latest ratings, click here.