CHR grew out of Top 40, which was developed in the late 1950s by Todd Storz and Gordon Mclendon, who found success in playing the 40 most popular records. By the mid-1960s, the rise of rock music and FM led to audience fragmentation and a revitalized, tighter format with less chatter, refined by programmer Bill Drake. The format was successful but was also criticized for being too slick and dehumanized. The move to FM was initially met with resistance, because FM was regarded as an alternative listening medium. As a result, Top 40 underwent another face-lift and became known as contemporary hit radio.

     The trade periodical Radio & Records (R&R) began using the term contemporary hit radio in 1980. The retitling of the format was orchestrated by consulting pioneer Mike Joseph. Joseph's CHR format featured a right playlist of about 30 records with up-tempo sounds, fast rotations, limited recurrence, chart hit countdowns, and no more oldies and declining records. At that time, CHR songs were by such artists as Blondie, Billy Joel, Christopher Cross, Queen, Dan Fogelberg, and Pink Floyd. The format moved to FM and became virtually nonexistent on AM as most radio listening shifted to the higher-fidelity broadcast system. Soon many broadcasters abandoned their soft rock and album-oriented rock (AOR) formats in favor of CHR.

     By the mid-198os, CHR became the highest-rated format. There were two or more CHR stations in many medium to large markets. Close to 800 CHR stations were on the air in 1984, and this number increased to nearly 900 in 1985. In 1987 and 1988 CHR was the number-one format in both New York City and Los Angeles, according to Arbitron market reports.

     As more stations flocked to the popular format, some turned to format segmentation as a way to broaden their core audience targets and to counterprogram against similar formats in their markets. In the mid-198os CHR split into two directions. The basic CHR format became a mass-appeal, I 2- plus format. A variation on that theme became "adult CHR," which went with softer announcing and added some oldies songs to the musical mix, attempting to appeal to the 25-to-34 demographic and divert audiences from adult contemporary (AC) stations. Some stations also went with hybrid formats, such as a Top 40/AOR format.

     CHR has undergone even more fragmentation in recent years. Today the most common variations include CHR/pop, CHR/rhythmic, and adult CHR/hot AC. CHR/pop most closely resembles the original Top 40 format. It is the most current-based format, playing the hottest-selling popular songs of the day. As a result, the music may vary from rock and pop to dance and alternative, depending on what is most popular at the moment. The style is fast paced, with lots of audience interaction with on-air personalities. Examples of CHR/pop artists include Madonna, Sheryl Crow, Hootie and the Blowfish, and Red Hot Chili Peppers.

     CHR/rhythmic is similarly fast paced and personality driven, but it is more dance oriented than CHR/pop is. More dance and urban hits are mixed into the format. Artists include Puff Daddy, En Vogue, Toni Braxton, and Baby Face.

     Adult CHR/hot AC focuses on a slightly older demographic of 25- to 34-year-olds and is dominated more by female artists. The format includes a fair amount of pop alternative. The format includes pop-rock artists such as Alanis Morissette and Natalie Merchant, as well as such traditional hot AC artists as Phil Collins and Gloria Estefan.

     Over the years, Top 40/CHR disc jockey announcing styles have changed. The early Top 40 jocks were heavy-voiced, shouting and cajoling their audiences. The mid-1960s change saw a reduction in disc jockey presence, with less chatter and more music. The 1970s saw even less aggressive, more mellow announcers. But with the reformation to CHR in the 1980s, the energetic, big-voiced personality reasserted itself. Irreverent morning shows grew in popularity. Still, audience loyalty is generally to the music and not to the disc jockey.

     CHR has replaced and generally become synonymous with the term Top 40, although many still refer to hits-oriented music stations as Top 40, and CHR is sometimes distinguished as using a larger playlist than Top 40. CHR stations feature little, if any, news and public-affairs programming. Syndicated features that reflect the all-hit nature of the format, such as American Top 40, are typically aired to help attract listeners. Nonmusic features such as sporting events are rarely programmed, however. Contests and promotions are an integral element of programming at CHR stations. CHR audiences are perhaps more receptive than those of any other format to imaginative and entertaining promotions.

     Its "more hits, more often" image led CHR stations to clus­ter commercials in spot sets after music sweeps. Commercials on CHR stations are designed to sound as slick and entertaining as the music they interrupt. Since CHR is production­ intensive, liners and catch phrases are vital to the format.

     Competition to CHR comes primarily from other CHR stations, which fragment the audience. Formats that share the highest percentages of CHR audiences include Spanish, alter­ native/modern rock, urban, and AC. AC attracts older demographics and women; AOR draws younger listeners and men. The prospects for CHR are good, however, because analysts believe radio listeners will always be interested in the hot new songs and artists of the day.

     After being dismissed in the mid-199os by some critics and advertisers as too teen oriented, CHR experienced a resurgence. An lnterep Research study attributed its success to an increase in the median age of listeners and to a wide range of music available and suitable to the format. A crossover of playlists became a boon to CHR, as CHR stations were able to play many of the same hits that get airtime on other young adult formats, such as alternative, modern AC, and adult album alternative. Today there is a variation on the format called rhythmic or "Churban" (a blend of CHR and urban).

     At the turn of the 21st century, CHR reached 14 million adults weekly in the 18-to-34 demographic. About 20 percent of the overall audience extends into the 35-44 range, and 8 percent are 45-54 years old. Most CHR listeners are female (56 percent). The CHR format audience is characterized as being active consumers of alcoholic beverages; restaurants; and all entertainment categories, especially movies; as well as of computers and electronic equipment. CHR has a fairly low cost per thousand (CPM}, because its audience generally does not have much money, although the young demographic does have very active spending habits.

     In 1998 CHR was the fourth most popular format, behind news/talk, country, and AC. Fall 1998 Arbitron ratings showed Top 40 to be rebounding in all dayparts except mid­ day. By 2002 there were 646 CHR/Top 40 stations in the United States. The format was the 11 th most popular for stations to carry.