How do TV Ratings Work with Time-shifted Viewing?


For years, the TV ratings showed us how many people were sitting down in front of the TV every day and evening to watch the shows that were scheduled as they were broadcast. But since the rise of the video cassette recorder in the 1980s, that presented a growing problem – how to account for viewing of shows after the time they originally aired?

Time-shifting, as it’s called, has only become more commonplace in today’s digital world thanks to the millions of digital video recorders (DVRs) that are in use. Remember, every single Foxtel iQ box and every single Fetch TV Mighty box is a DVR, and even the Fetch Mini is able to pause and resume live TV (as can many a smart TV without any extra hardware).

Time Shifted Viewing

To properly account for this delayed viewing, a solution had to be found, and that’s where UniTAM came in. The secret sauce is something known as “content matching” – and if you’ve ever used Shazam to identify a song, you’ve used the world’s most popular content matching service already!

For the ratings, OzTAM maintains a huge central database containing digital copies of all broadcast TV from the past 28 days (that’s a lot of TV). That data is kept for every region the ratings operate in. Key to the system is the ability of the UniTAM meters in ratings households to record the audio each TV plays back. Every night, that audio is included with ratings data sent back to base, and that audio is matched against that giant central database of shows. Very much like Shazam, just from the audio alone the computer can tell what the show was – as well as when it was watched, and how much of it was played back.

Only the bits of a recorded show watched in real time count – so any fast-forwarding is ignored. If you only watched 15 minutes of an hour-long show, the OzTAM computers record that as 15 minutes of viewing. If you record a show but don’t watch it, it doesn’t count towards the ratings at all. Those rules are in place to make sure only actual TV viewing gets counted in the ratings – rather than stuff on your DVR that you skip through because you didn’t want to watch it.

Those time-shift numbers feed into some of OzTAM’s most accurate ratings figures – the ‘As Live’ numbers from overnight, and the Consolidated numbers for shows watched within 7 and 28 days of their broadcast.

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