Well there are many reasons why Nielsen is still used. And most of the US isn't as accurate as a cable box. There are three ways that Neilsen collects data for TV usage.
1. Diary Markets - In most of the smaller areas of the US Nielsen sends diaries to people to keep track of what they watch for a month. The people will fill it out, send it back and get a small payment for doing so. In these markets only 4 months out of the year are tracked. The biggest problem with this is many people will wait until the last day of the month and fill it out based on what they think they watched. As some of these markets were switched to metered markets we have noticed shows on ABC, CBS, & NBC ratings have fallen and the ratings for FOX, CW & My TV have jumped.
Going for lunch, I will give more details later today about Nielsen.....
