Television ratings are an important measure used to assess the audience size and demographics of viewers for each TV show in order to determine a show's success and target commercials. Ratings data is collected from a sample of households using viewer diaries or set meters, and is calculated as a percentage of total TV households or persons watching. Ratings can be broken down into an overall rating score as well as ratings for specific demographic groups in order to help networks and advertisers understand their target audiences.

1. LATE NIGHT TELEVISION RATINGS
Math in the News
Issue 100

2. LATE NIGHT TELEVISION RATINGS
Click the image for a great overview video on howTV ratings work!

3. LATE NIGHT TELEVISION RATINGS
 What are television ratings?
 TV ratings are audience measures
 Ratings assess the following factors:
 What most people are watching
 How many people are watching
 Demographics of those watching (race, gender, age,
socioeconomic status, etc…)
 Each television show is analyzed based on these
factors and given a rating
Source: NielsenWiki

4. LATE NIGHT TELEVISION RATINGS
 Nielsen Ratings
 Most common type of rating used in the US and
Canada
 Used to measure the success ofTV shows
Source: NielsenWiki,
Nielsen.com

5. LATE NIGHT TELEVISION RATINGS
 How is ratings information collected?
 Based on a sample of television views
 A representative portion of the population to infer
behavior of the entire population
 Ratings collected using viewer diaries or set
meters
Source: NielsenWiki

6. LATE NIGHT TELEVISION RATINGS
 Viewer Diaries
 Self-report measure
 Set Meters
 Collect information such as:
 Programs and commercials
 Audience size
 Channel switching
Source: Nielsen
Wiki, Nielsen.com

7. LATE NIGHT TELEVISION RATINGS
 What areTV ratings used for?
 Success of aTV show
 To target commercials
 To determine viewing
What other uses ofTV ratings can you think of?
Source: Nielsen.com

8. LATE NIGHT TELEVISION RATINGS
 What variables are used to calculateTV ratings?
 TV HHs –TV households – the number of households
in the US with televisions
 PERS 2+ – Persons age 2 and older in the US
 Live, Live + SD (same day), Live + 7)—When
programs are viewed.
 Age demographic—2-11, 18-34, 18-49, etc , race,
gender, and other variables
Source:TV by the Numbers

9. LATE NIGHT TELEVISION RATINGS
 How are ratings calculated?
 Step 1: Data sent back to Nielsen
 Step 2:Total number of viewers and demographic
information is aggregated
 Step 3:Viewership data divided by total universe
ofTV watchers.
Source:YouTube viaTV by the Numbers

10. LATE NIGHT TELEVISION RATINGS
 How are ratings calculated? Cont…
 So, to summarize…
 Ratings are written as an number, so 25%
viewership would equal a rating of 25.0
Viewers
People Who Watch TV
=
Impressions
Universe
¬ A %

11. LATE NIGHT TELEVISION RATINGS
 How are ratings written and read?
 In addition to the rating score,TV shows are given a
share score.
Which type of score would likely be higher, rating or
share?Why?
Source:TV by the Numbers
Rating =
Total # Watching Program X
Total # with TVs
Share =
Total # Watching Program X
Total # watching TV

12. LATE NIGHT TELEVISION RATINGS
 How are ratings written and read? Cont…
 When the rating and the share are calculated for a
given show at a given time, it is written as a ratio:
Rating/Share
 For example, a show with a rating of 10.5 and a
share of 14.3 would be written as
10.5/14.3

13. LATE NIGHT TELEVISION RATINGS
 Example:
 Of a sample of 5,000 households with televisions,
3,493 televisions are tuned in and 342 are
watching television show x. What is the rating and
what is the share?
 Rating = 342/5,000 = 0.0684 = 6.84% = 6.4
 Share = 342/3,493 = 0.0979 = 9.79% = 9.79
 TV show x has a rating of 6.4/9.79

14. LATE NIGHT TELEVISION RATINGS
 Now let’s try a real world example!
 The premiere of TheTonight Show with Jimmy
Fallon had a total of 11.314 million viewers (out of
the entire population, not a sample)!
 If there are 115.6 millionTV HHs, what was the
rating of TheTonight Show with Jimmy Fallon on
it’s premiere night?
Source:TV by the
Numbers

15. LATE NIGHT TELEVISION RATINGS
 TheTonight Show ratings
 The premiere of TheTonight Show with Jimmy
Fallon had a rating of 9.7.
Rating =
11.314
115.6
= 0.097 = 9.7%

16. LATE NIGHT TELEVISION RATINGS
Day TV Show
Rating
TV Show
Share
Day 1 1.92 2.14
Day 2 1.9 2.16
Day 3 1.65 2.12
Day 4 1.7 2.1
Day 5 1.61 1.9
 What is the average rating
and share for thisTV show
over these 5 days?
 What rating trends can
you determine based on
the chart?
Average Rating =
1.92 +1.9 +1.65 +1.7 +1.61
5
= 1.76
Average Share =
2.14 + 2.16 + 2.12 + 2.1+1.9
5
= 2.084

17. LATE NIGHT TELEVISION RATINGS
 Now, let’s compare a fewTV shows on
specific demographics for people ages 18-49,
a target audience for Late NightTV
 Here are ratings for the 18-49 demographic
group for the week of May 5, 2014:
 TheTonight Show withJimmy Fallon – 1.04/5
 The Late Show with Dave Letterman – 0.51/2
 The Colbert Report with Stephan Colbert – 0.45/no
share found
Source:TV by the Numbers

18. LATE NIGHT TELEVISION RATINGS
 Question for consideration:
 TheTonight Show saw record ratings after Jimmy
Fallon, a younger host, took over for Jay Leno.
Stephen Colbert, star of The Colbert Report, is set
to replace Dave Letterman on The Late Show.
Given the ratings shown on the previous slide and
the rise in viewers for TheTonight Show after a
switch in host, how do you think Stephen Colbert
replacing Dave Letterman on The Late Show will
affect ratings?Why?

19. LATE NIGHT TELEVISION RATINGS
 More questions for consideration:
 What kind of specific demographic information do
you think The Disney Channel would want to
collect?What about Women’s Entertainment (WE)?
 Consider when it is most valuable to look at each
of the following and why:
 Overall rating
 Share
 Rating based on a certain demographic group