The methods and policies by which this data is obtained and compiled have changed many times throughout the chart's history.
Although the advent of a singles music chart spawned chart historians and chart-watchers and greatly affected pop culture and produced countless bits of trivia, the main purpose of the Hot 100 is to aid those within the music industry: to reflect the popularity of the "product" [the singles, the albums, etc.] and to track the trends of the buying public. Billboard has [many times] changed its methodology and policies to give the most precise and accurate reflection of what is popular. A very basic example of this would be the ratio given to sales and airplay. During the Hot 100's early history, singles were the leading way by which people bought music. At times, when singles sales were robust, more weight was given to a song's retail points than to its radio airplay.
As the decades passed, the recording industry concentrated more on album sales than singles sales. Musicians eventually expressed their creative output in the form of full-length albums rather than singles, and by the 1990s many record companies stopped releasing singles altogether [see Album Cuts, below]. Eventually, a song's airplay points were weighted more so than its sales. Billboard has adjusted the sales/airplay ratio many times to more accurately reflect the true popularity of songs.
Double-sided singles
Billboard has also changed its Hot 100 policy regarding "two-sided singles" several times. The pre-Hot 100 chart "Best Sellers in Stores" listed popular A- and-B-sides together, with the side that was played most often [based on its other charts] listed first. One of the most notable of these, but far from the only one, was Elvis Presley's "Don't Be Cruel" / "Hound Dog". During the Presley single's chart run, top billing was switched back and forth between the two sides several times. But on the concurrent "Most Played in Juke Boxes", "Most Played by Jockeys" and the "Top 100", the two songs were listed separately, as was true of all songs. With the initiation of the Hot 100 in 1958, A- and-B-sides charted separately, as they had on the former Top 100.
Starting with the Hot 100 chart for the week ending November 29, 1969, this rule was altered; if both sides received significant airplay, they were listed together. This started to become a moot point by 1972, as most major record labels solidified a trend they had started in the 1960s by putting the same song on both sides of the singles provided to radio.
More complex issues began to arise as the typical A-and-B-side format of singles gave way to 12 inch singles and maxi-singles, many of which contained more than one B-side. Further problems arose when, in several cases, a B-side would eventually overtake the A-side in popularity, thus prompting record labels to release a new single, featuring the former B-side as the A-side, along with a "new" B-side.
The inclusion of album cuts on the Hot 100 put the double-sided hit issues to rest permanently.
Album cuts
As many Hot 100 chart policies have been modified over the years, one rule always remained constant: songs were not eligible to enter the Hot 100 unless they were available to purchase as a single. However, on December 5, 1998, the Hot 100 changed from being a "singles" chart to a "songs" chart.[10] During the 1990s, a growing trend in the music industry was to promote songs to radio without ever releasing them as singles. It was claimed by major record labels[citation needed] that singles were cannibalizing album sales, so they were slowly phased out. During this period, accusations began to fly of chart manipulation as labels would hold off on releasing a single until airplay was at its absolute peak, thus prompting a top ten or, in some cases, a number one debut. In many cases, a label would delete a single from its catalog after only one week, thus allowing the song to enter the Hot 100, make a high debut and then slowly decline in position as the one-time production of the retail single sold out.
It was during this period that several popular mainstream hits never charted on the Hot 100, or charted well after their airplay had declined. During the period that they were not released as singles, the songs were not eligible to chart. Many of these songs dominated the Hot 100 Airplay chart for extended periods of time:
As debate and conflicts occurred more and more often, Billboard finally answered the requests of music industry artists and insiders by including airplay-only singles [or "album cuts"] in the Hot 100.[citation needed]
EPs
Extended play [EP] releases were listed by Billboard on the Hot 100 and in pre-Hot 100 charts [Top 100] until the mid-to-late 1960s. With the growing popularity of albums, it was decided to move EPs [which typically contain four to six tracks] from the Hot 100 to the Billboard 200, where they are included to this day.
Digital downloads, online streaming and bundles
Since February 12, 2005, the Billboard Hot 100 tracks paid digital downloads from such internet services as iTunes, Musicmatch, and Rhapsody. Billboard initially started tracking downloads in 2003 with the Hot Digital Tracks chart. However, these downloads did not count towards the Hot 100 and that chart [as opposed to Hot Digital Songs] counted each version of a song separately [the chart still exists today along with Hot Digital Songs]. This was the first major overhaul of the Hot 100's chart formula since December 1998.
The change in methodology has shaken up the chart considerably, with some songs debuting on the chart strictly with robust online sales and others making drastic leaps. In recent years, several songs have been able to achieve 80-to-90 position jumps in a single week as their digital components were made available at online music stores. Since 2006, the all-time record for the biggest single-week upward movement was broken nine times.
In the issue dated August 11, 2007, Billboard began incorporating weekly data from streaming media and on-demand services into the Hot 100. The first two major companies to provide their statistics to Nielsen BDS on a weekly basis were AOL Music and Yahoo! Music.[11] On March 24, 2012, Billboard premiered its On-Demand Songs chart, and its data was incorporated into the equation that compiles the Hot 100.[12] This was expanded to a broader Streaming Songs chart in January 2013, which ranks web radio streams from services such as Spotify, as well as on-demand audio titles.[13] In February 2013, U.S. views for a song on YouTube were added to the Hot 100 formula. "Harlem Shake" was the first song to reach number one after the changes were made.[14]
In July 2020, Billboard announced that they would no longer allow sales of physical/digital bundles to be reported as digital sales. This refers to songs being bought along with merchandise, either from an artists website or through another vendor. The magazine stated that this was a tactic generally used by certain artists to boost their chart positions. Instead, such physical releases are now only counted when they are shipped to the consumer, rendering the tactic "ineffectual".[15]
Remixes
A growing trend in the early first decade of the 21st century was to issue a song as a "remix" that was so drastically different in structure and lyrical content from its original version that it was essentially a whole new song. Under normal circumstances, airplay points from a song's album version, "radio" mix and/or dance music remix, etc. were all combined and factored into the song's performance on the Hot 100, as the structure, lyrics and melody remained intact. Criticisms began when songs were being completely re-recorded to the point that they no longer resembled the original recording. The first such example of this scenario is Jennifer Lopez' "I'm Real". Originally entering the Hot 100 in its album version, a "remix" was issued in the midst of its chart run that featured rapper Ja Rule. This new version proved to be far more popular than the album version and the track was propelled to number one.
To address this issue, Billboard now separates airplay points from a song's original version and its remix, if the remix is determined to be a "new song". Since administering this new chart rule, several songs have charted twice, normally credited as "Part 1" and "Part 2". The remix rule is still in place.
Recurrents
Billboard, in an effort to allow the chart to remain as current as possible and to give proper representation to new and developing artists and tracks, has [since 1991] removed titles that have reached certain criteria regarding its current rank and number of weeks on the chart. Recurrent criteria have been modified several times and currently [as of 2015], a song is permanently moved to "recurrent status" if it has spent 20 weeks on the Hot 100 and fallen below position number 50. Additionally, descending songs are removed from the chart if ranking below number 25 after 52 weeks.[16] Exceptions are made to re-releases and sudden resurgence in popularity of tracks that have taken a very long time to gain mainstream success. These rare cases are handled on a case-by-case basis and ultimately determined by Billboard's chart managers and staff. Christmas songs have been a regular presence on the Hot 100 each December since the relaxation of recurrent rules, culminating in Mariah Carey's 1994 recording "All I Want for Christmas is You" reaching #1 on the chart in December 2019.[17]
Adjustment of tracking week
Billboard altered its tracking-week for sales, streaming and radio airplay in order to conform to a new Global Release Date, which now falls on Fridays in all major-market territories [United States product was formerly released on Tuesdays before June 2015]. This modified tracking schedule took effect in the issue dated July 25, 2015.[3]