The model changed a while ago, thanks to DVR. People don't have to watch a TV show live in order for it to get credit.
You think binge-watching your favorite show weeks after its episodes air will help pump up its ratings? Think again. Live+3 television ratings metrics have changed things considerably.
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What they find is that even with streaming, the broadcast model still delivers a mass audience. So it's not a one-or-the-other thing, but both. That's why the networks won't totally give up on broadcast, but incorporate it into a multi-platform system.