Is there a way that digital television signals can send information on what’s being watched back to a central resource, giving absolutely accurate ratings?
Admittedly a certain amount of privacy is lost by this method, as it would somehow have to be tied into demographic stats, but, ignoring that for the moment, is it even possible to do?
For over the air signals unless the TV manufacturers are installing transmitters in your receiver, no.
If you have a cable box the cable company may already be tracking this data through their connection. If you have no box, I’d say no.
With Dish or Direct, if your receiver is hooked to an internet or phone line, they may be mining data.
They would need a camera to record which shows cause me to instantly doze off.
I’m 62 and most shows starting after 8Pm can do that. 
It’s possible now, you can take a van and ride around and find out what TVs in your area are tuned to what channels and this is with analog. You can buy a gadget that will tell you what frequency a cell phone is tuned to. (Because the cells are digital and scrambled for the most part you couldn’t hear anything but jibberish)
The problem is first of all cost. Second of all it is worthless data. Nielsen boxes today, not only record WHEN a TV is on, they also are capable of recording if anyone is in the room.
That was a problem when the boxes were introduced, people would turn the set on and leave. Advertisers don’t want to know the channel is on and no one is watching. They want to know how many people are actually watching.
The boxes now have sensors and the remotes actually require you to tap in your code so not only do the Nielsen boxes know if the channel is on AND being watched but WHO in the family is watching it.
Remember Nielsen isn’t a scientific poll, it is a measure of the audience the networks want to sell to.
If ten million people watch your show and only 10% are likely to buy and another channel has 5 million people and 22% of the people are likely to buy, the second channel, even with less viewers is a better deal.
Over-the-air television signals, even digital are one-way only. So is satellite TV and analog cable TV. Digital cable TV has some kind of two-way communication that allows you to order pay-per-view programming from your set top box.
In order for ratings data to be transmitted back to the broadcaster, your TV would need to be Internet enabled or at least have to be plugged into a phone line. This is how Tivo works as mentioned by the above poster.
I would imagine that there would be privacy concerns with any kind of nationwide ratings system and besides, Nielsen seems to be able to get adequate data based off of a fairly small sample set anyway.
Dish requires that your receiver be hooked to a phone line or you get charged an extra $5 per month. They could easily be downloading data indicating what channel were tuned and when.
But is it accurate? That’s what I’m concerned with. In my pokey little country of 20 million people, the sample size who provide ratings information is so small that I fear its lack of accuracy is giving false information back to the networks. When one household represents 50,000 people, yet the ratings information we get told seems to be considered absolute, it just bothers me. A 40 year old man wandering out to the kitchen is meant to imply that 50,000 men all wandered out to the kitchen at that moment?
Cite?
That’s not universal. No phone hook up to mine, and I’m not paying extra to not do it.