The commercial broadcast networks have always attracted the largest portion of the prime-time viewing audience. Through the 1960s, it was not unusual for the three networks (ABC, CBC, and NBC) to attract 85 to 90 percent of the available prime-time audience. The remaining 10 to 15 percent of the audience would be watching programming available on independent television stations or on public television stations.

Broadcast networks pay their affiliated stations in each local market to air the network offerings (this is called “network compensation”). In return, the networks retain the bulk of the commercial time for sale to national advertisers. This arrangement works well for both parties, as the networks attract audiences in each local market for their programming, which enables them to sell commercial time during such programs to advertisers wanting to reach a national audience. The local affiliated television stations receive high-quality programming, payment from the network, and the opportunity to sell the remaining commercial time (usually about one minute each hour) to local advertisers. However, with the increased costs involved in producing and securing prime-time programming and with smaller audience shares due to increased competition from cable, the networks have been reducing compensation payments to affiliates. In fact, some network programming is distributed sans compensation.

In the mid-1990s, the average 30-second prime-time network television advertising spot cost about $100,000. By the 2001–02 broadcast season, the average 30-second, prime-time network television advertising spot cost about $125,000. These same spots on a top-rated series average about $325,000, and such spots on low-rated network prime-time programs average about $50,000. Top-rated prime-time spots in local television markets cost as much as $20,000.

Because of network dominance in prime time, independent television stations (those not affiliated with a major broadcast network) have found it difficult to compete directly with network-affiliated television stations during these most desirable hours. In an attempt to allow independents to compete somewhat more fairly, during at least a portion of prime time, the Federal Communications Commission (FCC) enacted the Prime Time Access Rule (PTAR). The rule limits the amount of time a local affiliate can broadcast programming provided by the network. The most recent version of PTAR became effective in September 1975. It basically limited network-affiliated television stations in the 50 largest markets to no more than three hours of network (or off-network syndicated) programming during the four hours of prime time. The three-hour limit could be exceeded if the additional programming was public-affairs programming, children’s programming, or documentary programming, or if the additional programming was a network newscast that was adjacent to a full hour of local newscasts. Other exceptions to the three-hour limit included runover of live sporting events, and feature films on Saturday evenings. The FCC ended the PTAR in 1996; however, network offerings continue to be limited, now by convention, to three hours.

The growth of cable television in the 1980s resulted in a plethora of viewing options for the audience. Where audiences once had a choice of up to five, perhaps six options at any point in time, the new multi-channel environment provided viewers with more than 50 programming choices at once. Meanwhile, the development of the FOX network in the late 1980s, and on a slightly smaller scale, the Warner Brothers (WB) Network and the United Paramount Network (UPN) in the early 1990s, raised the prime-time status and visibility of independent stations. In addition, the advent of the videocassette recorder (VCR) also enabled viewers to rent prerecorded tapes, or to time-shift (watch programs that were recorded at an earlier time). The result of all this increased competition is that the networks’ share of the audience declined throughout the 1980s and 1990s. This was most evident in the prime-time hours. By the 2001–02 season, the networks’ share of the audience had dropped from previous heights of 80 to 90 percent to 50 to 60 percent. And as cable and VCR penetration levels (70 percent and 84 percent, respectively, in 2001) continue to grow, the fate of network television in prime time may decline still further.

Although prime-time programming has changed much during the history of television, three main trends continue: (1) the continued growth of the situation comedy; (2) the continued decline and perhaps death of the variety show; and (3) the consistent appeal of drama.

As new technologies, increased competition, and decreased regulation of television systems have developed throughout the world in recent decades, the notion of prime time has become more and more prevalent in systems outside the United States. Where television programming in other countries was once a special activity, often a limited number of hours roughly equivalent to American prime time, the move toward 24-hour programming has added new significance to the evening hours. Prime time is now a common marker in the days of citizens around the globe and this televisual “clock” has become part of every-day experience in almost every society.