[2][3] The Nielsen TV Ratings have been produced in the United States since the 1950–51 television season and statistically measure which programs are watched by individual segments of the population.

[4][5] The Nielsen sample included roughly 1,700 audiometer homes and a rotating board of nearly 850 diary respondents by the early 1980s.

Along with changing their counting methods, Nielsen also started emphasizing[clarification needed] their sample in 2003 in reaction to census shifts and requests from some industry sectors.

Nielsen's automated Local People Meter (LPM) technology was introduced in two cities: New York and Los Angeles.

While diary-based surveys concentrated on quarterly sweeps periods, the industry has been pushed toward year-round measurement due to the automated LPM system.

In 1996, Nielsen Media Research began tracking computer, internet, and video game usage through telephone surveys.

[9] After divestiture of NielsenIQ (the former ACNielsen consumer research business) in 2021, Nielsen became solely a media audience measurement and analytics firm.

Nielsen lost accreditation by the Media Rating Council (MRC) in 2022 due to inaccurate data reporting during the COVID-19 pandemic,[12] but regained it in April 2023.

Initial results indicated that time-shifted viewing (i.e., programs that are watched after the networks have aired them) would significantly impact television ratings.

Partnering distributors insert a "tag" into the program to be distributed on these services, which Nielsen then tracks through its meters system.

[29] Since specific demographics influence advertising rates, Nielsen provides statistics by categories including age, sex, race, economic class, and area.

[34] C3 was the metric launched in 2007, and refers to the ratings for average commercial minutes in live programming plus total playback by digital video recorder up to three days after.

In the 25 TV markets with the highest sales (e.g. New York, Los Angeles, Chicago, Denver), the Local People Meter (LPM) is measured.

Each year until 2018, Nielsen processed approximately two million paper diaries from households across the United States,[39][17] for November, February, May, and July—also known as the "sweeps" rating periods.

There is some public critique regarding accuracy and potential bias within Nielsen's rating system, including some concerns that the Nielsen ratings system is rapidly becoming outdated due to new technology such as smartphones, DVRs, tablet computers and Internet streaming services as preferred or alternative methods for television viewing.

[44] In June 2006, however, Nielsen announced a plan to revamp its entire methodology to include all types of media viewing in its sample.

[45] Since viewers are aware of being part of the Nielsen sample, it can lead to response bias in recording and viewing habits.

[52] A related criticism of the Nielsen rating system is its lack of a system for measuring television audiences outside homes, such as college dormitories, transport terminals, bars, prisons and other public places where television is frequently viewed, often by large numbers of people in a common setting.

Internet television viewing is another rapidly growing market for which Nielsen ratings fail to account for viewers.

[53] However, as noted in a February 2012 New York Times article, the computer and mobile streams of a program are counted separately from the standard television broadcasts, further degrading the overall quality of the sampling data.

[56] Responding to the criticism regarding accusations by several media executives (including Viacom CEO Phillippe Dauman and former Fox Entertainment Group chief operating officer Chase Carey) that it failed to count viewers watching television programs on digital platforms, Nielsen executive vice president of global product leadership Megan Clarken stated in an April 2015 summit by the Coalition for Innovative Media Measurement that the company can count digital viewers in audience and demographic reports but is unable to do so under the current set of rules devised by networks and advertising industries last revised in 2006.

[58] In 2004, News Corporation retained the services of public relations firm Glover Park to launch a campaign aimed at delaying Nielsen's plan to replace its aging household electronic data collection methodology in larger local markets with its newer electronic People Meter system.

[61] In September 2020, Nielsen began releasing a weekly list of top 10 television shows most watched on streaming platforms or subscription video on demand (SVOD).

[65][66][67][68][69] (Average primetime viewership) Starting in September 2020, Nielsen releases a weekly list of top 10 television shows most watched on streaming platforms, or subscription video on demand (SVOD).

[159] This immediately attracted attention by mainstream media, such as Variety, Hollywood Reporter, Deadline and Business Insider.