Over the years, the ratings firm Nielsen has used every trick in the book to try to accurately tell who's watching which TV show. It started with diaries, somewhat unreliable since the viewer had to remember to fill them out. Then there were those set top boxes that read which channel you were watching. Along came the Internet and yet another new tracing element was added. 

But now Neilsen in the U.S. is trying something new: a kind of ratings Smart Watch. The idea is not just to capture what an individual is looking at on the tube, but what those who may be around them are watching as well. They're called "co-viewers" and up till now, it was tough to know how many others were watching what the chosen ratings collector was seeing. 

"Nielsen will use new wearable measurement devices that resemble a smart watch that will be placed on the wrists of Nielsen panelists and capture audio from TV events, shows and movies, allowing for more passive measurement the company believes will create result in a more accurate picture of how many people are watching a given program."

Hard to say how much this will boost the numbers of already successful programs like "Tracker" or The Super Bowl, which many people watch together at the same time. But it sure beats the diary system for real time accuracy. 

There's no word on whether this "watch that watches what you're watching" will be used by Numeris or any other service in Canada.

Nielsen Makes New Bid to Capture ‘Co-Viewing’ as TV Season Approaches