Every TV viewer or radio listener has heard about ratings, and how they rise and fall. As a consumer we may wonder if the ratings to our favorite program continue to fall will they take my show off the air? As a marketer we want to know how the growth or decline in ratings for a radio station will affect our advertising.  Ratings impact the cost and effectiveness of our advertising, and also impact the other data we use to create a campaign. Understanding TV and Radio ratings and related data is imperative if we are going to buy them for our business.

What Are Ratings

A rating is nothing more than a percentage of the total audience. If a program gets a 1.0 rating, that means that 1% of the measured audience in a specific geography watched or listened. A rating can be derived for a specific demographic, such as Adults between the ages of 25-54. If we measure a radio station’s audience of A25-54 in the New York marketplace and the station has a 1.0 rating, then 1% of 25-54 Adults in the New York marketplace listened to the station. Ratings can be derived against any demographic and in any geography.

It is important to understand that audience sizes can change over time. While populations in some parts of the country have decreased over time others have increased. And with the proliferation of different TV viewing devices the total TV audience in America has increased. At the same time, because there are more ways to consume TV (broadcast, cable, stream) the audience has splintered. Same with Radio. Prior to Covid ratings for broadcast and cable were dropping as more people streamed TV.


Geography in TV and Radio is predefined for us. Usually, ratings are taken for population centers or markets. Advertisers cannot arbitrarily define a market, that is done by Nielsen. Ratings that are delivered for smaller geographies, such as a county, are often extrapolated from the market data. A single county usually does not have the sample size to generate it’s own ratings. The exception would be extremely populated counties such as New York County (Manhattan.


Ratings are measured either electronically or from a diary. In all cases, only a small percentage of the population is measured. The reporting company, usually Nielsen Media Research, tries to measure a “representation” of the actual population base. They try to match the demographics of the target geography being measured. Once Nielsen has what it thinks is the correct sample size it will either record viewing or listening habits. Measurement can be done electronically or through diaries kept by the sample audience.

Nielsen then uses this statistical sample to extrapolate the viewer or listenership.  Select households that are part of Nielsen’s TV measurement are supplied with a black box, which is essentially a computer and modem, that transfers viewing information in real time. That is how Nielsen is able to provide overnight ratings.  In larger markets people in the measuring sample wear a “Portable People Meter” (PPM) which records all of the listening and watching. PPM’s are about the size of a small cell phone. Diaries are more common in smaller markets.  In diary markets people are asked to fill out a diary daily, and turn that in at the end of the reporting period. While diaries are not as accurate as electronic measurement they do provide a solid measurement tool.

Ratings Share

Ratings are the basis for another valuable measurement statistic, Share. Perhaps you heard that a program got a 1 rating and a 10 share against A25-54. A Share is the percentage of people who were watching or listening during the given time period. In our example, a 1 rating is 1% of the total A25-54 population in the market. And the Share states that 10% all 25-54 year olds in the market who were watching TV at that time saw the program. Share gives us a better idea of the popularity of a program or station and provides perspective on dominance.

Understanding TV and Radio Ratings

Understanding TV and Radio ratings is the all-important first step in learning how to construct a TV or Radio buy. With the knowledge of how many people are watching or listening and what percentage of our target demographic is watching, we know how many commercials we need to purchase. Ratings, and their associated costs also help us choose the programs or stations for our plan. Because, as ratings fluctuate, so do the costs of advertising. The better you understand the nuances of ratings the more efficiently you can buy advertising. Pay close attention to ratings.