Understanding Nielsen TV Ratings

When we hear that ratings are up or down, we should evaluate the context which the information was shared. But what are ratings and share?

Nielsen, the longtime giant of media measurement, collects viewing habits from a sample size to estimate the viewing patterns of a nation or region. These results are published in “overnight” reports or after February, May, July and November (also known as Sweeps months).


The ratings is an estimate of the percentage of the audience watching the program. If “News at 6:00” has a household audience rating of 11, this means that 11% of the market (city or region) is watching News at 6:00 on TV. The other 89% may be outside playing basketball or doing yoga.


The share is an estimate of the percentage of how many households using television are watching the program. If “News at 6:00” has a market share of 20, this means that 20% of the homes watching TV at 6:00 are watching the news. Because this eliminates anyone doing chores or playing playing basketball or doing yoga and not watching TV, the share will be higher than the rating because the total possible households of television watchers is smaller.

Media watch websites like Programming Insider and Spots n Dots or Cynopsis highlight overnight ratings in their email subscriptions.