I’m sure you must have read the headlines. You know, the kind where we get to hear how badly a highly anticipated show did, just hours after it came on TV. Or how well a particular show is doing against shows on competing TV networks? My question is, how do these people measure these numbers, and measure them so quickly?

Think about it for a second. Television is, for the most part, a broadcast medium. That is, our television sets mostly just receive data and hardly ever send anything back. You could say that this communication channel is mostly one way.

The Wikipedia page on Nielson ratings sheds some light on the matter:

One involves the use of viewer “diaries,” in which a target audience self-records its viewing (or listening) habits.

I’m not sure how much trust I can put in this methodology. But there is hope:

A more technologically sophisticated system has used Set Meters, which are small devices connected to every television in selected homes. These devices gather the viewing habits of the home and transmit the information nightly to Nielsen through a “Home Unit” connected to a phone line.

But this still doesn’t sound like a good solution. I also read somewhere that another popular methodology involves calling up randomly selected people and questioning them about their viewing habits!!

These days the situation is still a little bit better. Set-top boxes and  DVRs are becoming increasingly prevalent. These devices are significant more powerful and smarter than their ancestors, in the sense that they already do a fair bit of communication with your cable company, and hence it is conceivable that they enable collection of more accurate usage statistics.

Overall, it seems like a hard problem to me, since television has traditionally not been a connection oriented medium. This might change moving forward as IPTV and on-demand videos become more common. If you have some more information on the nitty-gritties of how this all works, please do share!