There is a simple definition of a Nielsen rating: The % of persons or households watching a
Television program. So, a 5 household rating would indicate that 5% of U.S. TV
Households watched that program, right?
As with most things, it’s a bit more complicated.
The size of television audiences change constantly as
viewers tune in and out of different programs. Think about a 3 hour baseball
game. Some die-hard fans may watch the
entire game, but many viewers will watch a few innings – including a good
number who will tune in to check the score when other programming goes to commercial
breaks.
To calculate the rating for the complete telecast of the
game Nielsen measures every minute of the program and then produces an
average. This is an important
concept: the Nielsen rating is the
average minute audience for a program. A
5 household rating for a TV program indicates that 5% of U.S. Households were
watching a program during an average
minute. It is NOT an estimate of
the total number of persons who watched a program.
Why the focus on average minute audiences? Average minute audience estimates help
advertisers understand the size and dimensions of the audiences that viewed
their commercials.
Let’s look at the ratings for a one hour program, and this
time we will use ratings for Males and Females 18-49 instead of Households.
Date
|
Time
|
Net
|
Program
|
Nielsen Rating MF 18-49
|
Nielsen Program Rating
|
2/13/2016
|
8:00PM
|
ESPN
|
30 for 30: Broke
|
2.3
|
2.6
|
2/13/2016
|
8:15PM
|
ESPN
|
30 for 30: Broke
|
2.4
|
2.6
|
2/13/2016
|
8:30PM
|
ESPN
|
30 for 30: Broke
|
2.7
|
2.6
|
2/13/2016
|
8:45PM
|
ESPN
|
30 for 30: Broke
|
2.9
|
2.6
|
The average minute audience (the rating) for the entire
program is 2.6, but notice the variation from quarter hour to quarter
hour. The audience for the final quarter
hour is over 25% larger than the audience for the first quarter hour (2.9 vs.
2.3).
If you are a marketer with ads in the first quarter hour of
this program you would not pay for the full program rating, you would pay for
audience that was actually delivered for your ad – the 2.3 rating. The 2.3 rating is the average minute audience
estimate for that quarter hour. This is
important because deals between marketers are networks are based on delivering
a specified number of rating points. As
a marketer you are basically buying ratings points.
To make things more complicated, Nielsen also factors in the
audiences that watch a program following its initial live airing with DVRs and
on-demand viewing. These ratings are
labeled as:
·
Live+SD (Live plus Same Day. Live viewing + any viewing until 3AM following
the initial telecast.)
·
Live+3 (Live plus 3 days. Live viewing plus any
viewing in the following 3 days.)
·
Live+7 (Live plus 7 days. Live viewing plus any viewing in the
following 7 days.)
To read up on how Nielsen estimates media audiences, you can
follow the link below, and future posts will cover how media audiences are
estimated for marketing purposes, including how Gross Rating Points are
calculated and what they mean for media planning. Stay tuned.
