TV Ratings and What They Mean

It's premiere week, which means the 2019 fall TV season is here and our favorite network shows are finally back from summer hiatus. Over the course of the next couple of weeks, the five broadcast networks (ABC, CBS, NBC, FOX, and The CW) will debut more than 15 new shows. So how do the networks measure the success of their new shows over their established series? Here's what you need to know about TV ratings and the other metrics that determine a show's fate.

Network TV, premium cable, and streaming

Before we jump into TV ratings, it's important to know the different ways channels make money. While all these services gain revenue through various means, the main difference is that broadcast networks and cable (TNT, AMC, USA, etc.) profit by selling advertising space during programming while premium cable and streamers rely on subscriptions. All channels use viewer analytics to decide if a TV show is profitable and worth keeping on their schedules, but how the data is gathered and parsed depends on the platform.

While networks air content year-round, they still follow the traditional TV season of September-May. Premium cable and streaming platforms constantly debut new content throughout the year. The New York Times estimates that at least 70 new programs will debut this fall across all content providers, including series from Apple TV+ and Disney+.

How do TV ratings work?

Network and cable TV ratings have been gathered by Nielsen Media Research since 1950. There's a lot that goes in to measuring ratings, but basically, Nielson chooses a random sample of diverse American households and installs meters to keep track of what's being watched. They also monitor how long you watch, how many people are watching, and the device used. All of this information is compiled overnight and sent out to networks.

An important thing to know about Nielson ratings is that they are based on statistical sampling and are not a comprehensive measure of every person watching TV in America. According to Nielson, there are 120.6 million TV households in the United States, but only around 46,000 are sampled. The numbers reported are estimates of the 120.6 households based on the viewing habits of the sample population.

These TV ratings help calculate how much a network can charge advertisers for airtime during specific programs. One of the most important pieces of data used to determine ad pricing is the adults 18-49 rating share.

• Adults ages 18-49 are known as the key demographic because advertisers believe they have the most disposable income and least brand loyalty, which may make them more susceptible to advertising.
• Rating is the percentage of total TV households tuned into a program at a given time. So if a show has a 1.0 rating, it means that 1% of those 120.6 million households watched that program. This number is always out of the total estimated TV households and does not factor how many of those total households actually had their TVs on.
• Share is the percentage of households that watched a program out of all the households that were actively watching TV at a specific time.

Let's break this down. Variety reported that the highest rated network series of the 2018-2019 season was This Is Us with an average 3.8/16 rating share in the key 18-49 demo. That means that 3.8% of all TV households watched This Is Us on a given night and 16% of all people actively watching TV during that timeslot.

So what is considered a good rating? It's all relative. How "good" a show's ratings are can depend on many things, like how many households the channel is offered in, the demographic of the channel's audience, and how high a program's ratings are in comparison to other shows in the same timeslot. Low ratings don't always mean cancellation as that program may also be profitable through streaming deals, syndication, international ratings, and social media influence. All of this is taken into account when networks decide their upcoming schedules during Upfronts each May.

Want to know more about how the TV industry works? Learn more about the three stages of production and the crew members you should know on set.