Subject: Re: Unfair TV Ratings - Ron Reagan show (TP/30Something) From: phil@eecs.nwu.edu (William LeFebvre) Date: 1991-08-30, 08:22 Newsgroups: rec.arts.tv,alt.tv.twin-peaks In article <56773@apple.Apple.COM>, unknown@Apple.COM (Matt Ackeret) writes: |> For one thing, we didn't quite define what we are attempting to take |> a statistically valid sample OF. |> |> Is it all TV owning families? I believe that it is all TV *watching* families (Nielsen doesn't care if you own the TV you are watching). But I know that they also collect statistics on how many families (or maybe I should say "residences") actually own, or have in their residence, a TV. |> Where do they get the people to join? They select them at random (see my previous post). They probably use information on property ownership from various governmental agencies to determine what is a residence. Then they call them on the phone. What if they don't have a phone? I imagine (I'm making an educated guess here) that they visit the home in person. |> I cannot prove that it isn't a statistically valid sample, I just |> would guess that the determination of who becomes a Nielson family is |> skewed to a more affluent crowd in some way or another. Wrong. I know that they have families in government subsidized and low-income dwellings. |> There are just lots of things that come to mind that could very well |> affect the choice of families. |> |> I very well could be wrong... but I don't THINK that I am. I THINK you are. Look people, A.C. Nielsen Company has in its employ a large team of statisticians and actuaries to make sure that its sampling techniques are reasonably valid. Do you think that such result-skewing possibilities haven't occurred to these people? Of course they have, and the sampling technique is designed to eliminate such possibilities: it is designed to be as representative as possible. I'm NOT saying that the Nielsen ratings are representative. And in fact I would be interested in hearing any educated arguments for or against their accuracy. What I AM saying is that the company is at least trying to make it representative. William LeFebvre Computing Facilities Manager and Analyst Department of Electrical Engineering and Computer Science Northwestern University