I read this definition of ratings vs share "The difference between rating and share is that a rating reflects the percentage of the total population of televisions tuned to a particular program while share reflects the percentage of televisions actually in use."
But I am confused as it says both "televisions tuned to a particular program" and "televisions actually in use."
How can a TV be tuned to a program if it isn't in use????
So does rating actually mean the TVs that exist in the US - the potential - if they were all turned on? And does share mean the literal number of TVs showing a particular program?
Why bother with rating? It seems a bizarre measure.
rating = proportion of TVs watching the show out of all TVs that exist
share = proportion of TVs watching the show out of all TVs that are turned on
16
Decent_Opposite_3470Apr 15, 2026
+1
yeah the rating thing is kinda weird metric when you think about it but i guess advertisers want to know potential reach too? like if there's 100 million households with tv and 20% rating means 20 million could theoretically see your ad even if only half the tvs are actually on
share makes way more sense for actual competition between shows since it's just what people are actually watching in that moment
1
MaskedBandit77Apr 15, 2026
+5
Rating is a better measure of how popular something is. A popular show will cause people to turn on TVs that wouldn't otherwise have been on.
Also, you want to be able to compare the ratings of a show from episode to episode. If you use share to measure that, you could have a situation where more people watched one episode, but it has a lower share because more people happened to be watching TV that week.
5
QuintoBlancoApr 15, 2026
Most people don't care about how shows compete to other shows. The exception is if a network has two shows that target the same demographic. Obviously, for the network it make sense to give preferential treatment to a show that 'outcompetes' another show, and they can correct for different time s****.
But advertisers only care about how many people they reach in their target audience.
0
NearbyCow6885Apr 15, 2026
But they’re not actually counting all televisions. There’s something like 30,000 actual families they track the viewing habits of, and then they extrapolate that to an estimated 120 million tv-watching families. It’s a ridiculously small sample size.
At least that was what I’d heard maybe 20 years ago … maybe they’ve changed their practices with the increase of viewing options. But back then that’s why a show could be cancelled due to low ratings only to be brought back by high dvd sales.
0
VoraciousChallengeApr 15, 2026
+1
How are you calculating your sample size? At what CI?
By my back of the envelope math, 30k/120M seems like more than sufficient size for this. Sample size does not scale linearly with population size.
1
NearbyCow6885Apr 15, 2026
-1
No, that’s fair… from a strictly mathematical perspective that’s a reasonable sample size.
But when you consider just how many television programs (and even genres) there are it means a small number of individuals is determining the millions of viewers. For instance Season 1 of The Office averaged a 5.0 million viewership. When means roughly 1,250 actual tvs were being counted. Which is not a lot of individuals and depends highly on the specific distribution of those tv’s across the country.
-1
VoraciousChallengeApr 15, 2026
+1
>small number of individuals is determining the millions of viewers
That's what a sample size is though. It's the formula to determine how many people need to be asked in order to get an accurate a picture over a given population.
I don't understand your point that its accurate from a mathematical standpoint but yet also not accurate based on... vibes?
1
NearbyCow6885Apr 15, 2026
-1
My point is it’s important to understand what a 5.0 million share actually means. And to recognize the limitations of the model.
A 5.0 million share does not mean 5.0 million people definitely watched a show, it means 5.0 million people _probably_ watched it based on these assumptions.
And those assumptions can be wrong. As evidenced by shows that were cancelled because of low ratings only to be brought back when viewership was confirmed via other means.
-1
NearbyCow6885Apr 15, 2026
+1
Also worth pointing out this has not been the only criticism of Neilsen’s model. In sept 2021 they lost their accreditation for a year and half because viewership assumptions drastically changed during covid and their models did not change, resulting in them drastically underreporting viewership numbers.
All addressing my underlying point, there are a lot of assumptions being made to extrapolate out the final published ratings numbers. And those assumptions can be wrong.
1
mfGLOVEApr 15, 2026
+2
All I know is Nielsen sent me $2 cash in the mail last week and asked me to sign up for a $5 survey. I didn’t do it, but I’m still $2 richer for doing nothing!
2
MaskedBandit77Apr 15, 2026
+1
It's the difference between a million people watching something at 3 pm on a Sunday afternoon and a million people watching something at 3 am on a Tuesday.
1
HenriDuflotApr 15, 2026
+1
Think of rating as a percent of a given universe. When it comes to TV ratings, the universe can widely vary, but the most common one in the press is Households. So if there are 125 million households in the US, a TV show HH rating of 1 means that 1% of all homes with a TV watched that particular show. For Share, similar calculation, but the universe is of TV sets in use.
1
JonStricklandApr 15, 2026
You're on the right track.
So, ratings gives you a percentage of TVs tuned into a particular program out of all potential TV views. Let's say there are just 100 TVs, and 20 of them are tuned into, I dunno, Ghost Huggers or something. That means 20% of all potential TVs were tuned into Ghost Huggers, and ratings are derived from that percentage.
But not all 100 of those TVs were actually turned on. Let's say another 20 of the TVs were turned off cause there was a meteor shower over Cleveland and people got excited. So only 80 TVs were in active use at the time Ghost Huggers was on. Share would tell you how Ghost Huggers performed against other programming that was on across those other 60 active TVs.
So the first number, the total percentage of possible TVs that could tune in, gives you the audience size. That's what you take to advertisers so you can say "Blim Blam Cigarette Gum ads will be in front of 20% of all potential TV households if you advertise on Ghost Huggers."
The second number lets you say "Wow, Ghost Huggers is really performing well against Ice Chicken Truck Wranglers."
Also, I haven't watched television in about 30 years. . . . .
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