The ratings process
OzTAM TV ratings are television audience estimates based on actual viewing behaviour in homes across Australia’s mainland metropolitan markets and nationally for subscription television.
OzTAM’s TV ratings service provider, Nielsen TAM, collects and produces ratings data on OzTAM’s behalf.
Once a household has been recruited onto the panel, all television sets in that home are monitored by a sophisticated metering system called Unitam which captures viewing to all broadcast television channels on all TV sets in that home.
The Unitam meter records and stores all information about viewing including:
- who is watching
- the time, duration and date
- whether each TV is on or off
- the television audio signal
All household residents and any guests register their presence using a remote control. The panel members do not need to do anything else for OzTAM to capture their viewing.
Every night the data collected by the Unitam meters is retrieved automatically via modem telephone software in a process known as 'polling'.
A sophisticated ‘content matching’ process of matching the audio captured from the panel homes to a reference library of all available TV broadcast channels within each market is used to measure viewing to individual channels, whether the viewing is Live (i.e., as the program actually went to air) As Live (paused or recorded programming played back before 2am on the same day of the original broadcast) and Time Shift to 7 (recorded broadcast content played back through the TV set after the same Research Day and within seven days of the original broadcast). From April 2016, OzTAM also offers Consolidated 28 viewing in its television ratings database, capturing viewing through the TV set up to 28 days after the broadcast first went to air.
The production system collates, processes, analyses, validates, weights and produces a final report of each household's viewing.
Once the production processes have been completed, the television program schedules provided by the TV networks and ratings are integrated. All data undergoes rigorous quality control both electronically and manually.
The output is a database of minute-by-minute viewing audiences. Individual households and viewers are anonymous; only demographic profile data is released.
Results are provided each morning and this Overnight data (programs that were watched as they actually went to air or recorded that day and played back before 2am that morning) is available to OzTAM subscribers via a secure website.
Because programs sometimes run beyond their scheduled time, for example, a football match goes into overtime or a news broadcast is extended because of a major story, OzTAM’s Overnight ratings are based on Preliminary times – that is, according to the program schedules the television networks provide prior to broadcast.
In the event a program’s actual telecast time differs from the schedule, TV networks have until the afternoon following broadcast to inform OzTAM. The next day OzTAM republishes the ratings based on Confirmed times.
- For example, on Monday morning, OzTAM supplies Preliminary Overnight ratings for programs that aired on Sunday (the day before). On Tuesday morning, OzTAM will reissue Overnight ratings for Sunday based on Confirmed times.
Along with Preliminary Overnight ratings, each morning OzTAM releases Consolidated 7 data for the same Research Day a week earlier, incorporating Live and Playback viewing within seven days of the original broadcast (OzTAM's Time Shift Viewing service).
- For example, on Monday morning, OzTAM supplies Consolidated ratings for programs that aired the previous Sunday (8 days earlier).
From 2016, OzTAM also offers 28-day Time Shift Viewing in its elemental database, allowing clients to track viewing of television programs played back through the TV set up to 28 days after the program went to air. Consolidated 28 data is available 29 days following the research day of the original broadcast.
See this one-page PDF on The Ratings Process for an illustration.
More about the OzTAM Panel
Please note OzTAM uses a different methodology to capture viewing of internet-delivered TV content. Please see the Video Player Measurement section for details.