Singles charts

A record chart also called a music chart is a ranking of recorded music according to popularity during a given period of time. Examples of music charts are the Hit parade, the Billboard Hot 100 or Top 40.

Many different criteria are used in different charts, including sales of records, cassettes and compact discs, the amount of radio airplay, and since the introduction of digital technology, the number of downloads and the amount of streaming activity.

Some charts are specific to a particular musical genre and most to a particular geographical location (although download charts are not easily pinned down in this way). The most common period of time covered by a chart is one week with the chart being printed or broadcast at the end of this time. Summary charts for years and decades are then calculated from their component weekly charts. Component charts have become an increasingly important way to measure the commercial success of individual songs.

A chart hit is an extremely popular recording, identified by its inclusion in a chart that uses sales or other criteria to rank popular releases. Chart-topper and related terms (like number one, No. 1 hit, top of the charts, chart hit, and so forth) are widely used in common conversation and in marketing, and are loosely defined. In North America, the weekly charts from Billboard magazine are most often referenced (quite often internationally, as well), particularly the Billboard Hot 100 singles chart and Billboard 200 album chart, although there are many other charts and sources. Because of its value in promoting recording artists and releases, both directly to the consumer, and by encouraging exposure on radio, TV other media, chart positioning has long been a subject of scrutiny and controversy. Chart compilation methodology and data sources vary, ranging from "buzz charts" (based on opinions of various experts and ), to charts that reflect empirical data such as retail sales. Therefore, a chart-topper may be anything from an "insiders' pick" to a runaway seller.

...
Wikipedia