Each day of the Winter Olympics, NBC reports how many viewers watched the previous night’s coverage, and analysts and television executives try to divine what those numbers mean.

But NBC isn’t presenting traditional Nielsen ratings, the television standard for decades. Instead, for prime-time viewing, the network primarily cites a recently created standard of its own making called total audience delivery, or TAD. It takes the ratings from the broadcast channel NBC and cable channels like NBCSN that are showing the Olympics and combines them with viewership across various streaming platforms to produce one number.

NBC’s number-crunching is only partly a marketing campaign. It is principally the latest attempt at a valid head count in an industry where no one seems to be able to measure the crowd. Viewers are spread too far and wide, no longer huddled around the TV.

NBC also used TAD during the Rio Olympics two years ago, but this is the first time it has sold advertising based on it. Guarantees to advertisers about how many people will watch commercials will be based on TAD, not Nielsen household ratings. As television audiences shrink, that is a big deal for the network, which says its national ad sales for the Winter Games recently passed $900 million. And NBC Universal has committed $8 billion for the media rights to the Olympics through 2032.