GENERAL INFORMATION

SALES
Data for Billboard's sales charts, which include all album charts, are compiled by Nielsen SoundScan from a universe of retailers that represents more than 90% of the U.S. music retail market.

The sample includes not only music stores and the music departments at electronics and department stores, but also direct-to-consumer transactions and Internet sales (both physical albums via Internet, and ones bought via digital downloads). A limited array of verifiable sales from concert venues is also tabulated. All sales charts use the entire Nielsen SoundScan panel.

The Nielsen SoundScan system utilizes that same point-of-sale that music merchants use to track their inventory, so an itemized receipt from one's last visit to a music retailer essentially doubles as a ballot cast for our charts.

AIRPLAY
Billboard's radio charts are compiled using information tracked by Nielsen BDS, which electronically monitors radio stations in more than 140 markets across the United States. The BDS system looks for an audio fingerprint, i.e. a characteristic that differentiates a song from all of the other ones that it tracks.

Certain airplay charts are based on the number of plays that each song received in a given format that week: Mainstream Top 40, Adult Contemporary, Adult Top 40, Alternative, Triple A, Active Rock, Heritage Rock, Mainstream Rock, Mainstream R&B/Hip-Hop, Rhythmic, Adult R&B, Christian AC Songs, Gospel Songs, Dance Airplay and Smooth Jazz Songs. Others are based on audience impressions: Hot 100 Airplay, Rock Songs, Hot Country Songs, Rap Songs, Christian Songs, Hot Latin Songs and Latin airplay charts.

The audience charts cross-reference BDS data with listener information compiled by the Arbitron ratings system to determine the approximate number of audience impressions made for each plays. Thus, a song that plays at 4 a.m. does not count as much as one played at 4 p.m., and a station with a large audience will influence the chart more than either a station in a smaller market or one with a specialized format that attracts less audience.

With few exceptions, stations tracked for Billboard by BDS are commercial stations.

MIXING DATA
Most of the charts in Billboard are either pure sales or radio charts. The only exceptions in which we mingle sales and radio data are two of our signature charts: the Billboard Hot 100 and Hot R&B/Hip-Hop Songs (as well as two charts based on the same data feeds as the Hot 100: the Hot 100's Bubbling Under chart, which ranks the top 25 titles that have not yet reached the Hot 100, and Heatseekers Songs, which reflects the most popular songs by new or developing acts, defined as those who have never appeared as a lead artist in the top 50 of the Hot 100, or the top 50 of Hot 100 Airplay prior to Dec. 5, 1998).

We use both pools of data because while the consumer's decision to purchase is a significant vote of popularity, singles have a job that extends beyond being a sales vehicle: to capture radio play and, hopefully, stimulate album sales.

These two hybrid charts each use formulas to mix Nielsen SoundScan sales with BDS audience. The Hot 100 utilizes the a la carte sale of downloaded tracks with sales of the few retail-available singles that are still shipped to stores. The chart also factors in streaming audio and video data (both on demand and passive) from AOL and Yahoo. The Hot 100 utilizes audience from all popular formats monitored by BDS. The Hot R&B/Hip-Hop Songs chart meshes sales with audience data from R&B and hip-hop stations.

ADDITIONAL CHARTS
There are a few Billboard charts that are made up of data from different sources. Here's how other charts are compiled:

Billboard's Social 50 chart ranks the most active artists on the world's leading social networking sites. Artists' popularity is determined by a formula blending their weekly additions of friends/fans/followers with artist page views and weekly song plays, as measured by Next Big Sound.

Uncharted is a listing of the top new and developing artists who have yet to appear on a major Billboard chart, regardless of country of origin. Rank is based on a formula incorporating streamed plays, page views and fans according to MySpace, as well as sources tracked by online aggregator Next Big Sound, including YouTube, Facebook, Twitter, Last.fm, iLike and Wikipedia, among others. In order to appear on Uncharted, acts must be registered MySpace Music artists and have not appeared specifically-outlined Billboard charts (more than 80 overall).

Billboard's Ringtones chart uses sales data from Nielsen Mobile's RingScan service, which compiles sales information from the majority of ringtone retailers in the U.S. market. The chart ranks sales of master (not polyphonic or monophonic) ringtones.

The Dance Club Songs chart is compiled from reports from a nationwide panel of club DJs, detailing the tracks that elicit the most audience response.

Billboard's Smooth Jazz Songs chart combines airplay data from stations monitored by BDS with those that submit playlist reports online.

The Christian CHR, Christian Rock, Soft AC/Inspirational and Christian AC Indicator charts are compiled from playlist reports that stations playing those genres of music submit online.

THE CHART WEEK
Generally, charts reflect sales and airplay between Monday and Sunday of any given week. However, the mixed data charts, such as the Billboard Hot 100, use an airplay cycle of Wednesday through Tuesday.

Charts are refreshed every Thursday on billboard.com and billboard.biz and reflect the date of the Billboard issue in which they appear; online-only charts display the same corresponding date.

The printed magazine first reaches newsstands on Friday. Each issue is dated based on the end of its publication week. Thus, the Billboard that reaches newsstands on Friday, March 19, for example, is dated Saturday, March 27.

RULES AND EXPLANATIONS

GLOSSARY OF TERMS
Below is a list of awards you'll see on various Billboard charts and their meanings.

BULLET
Where included, indicates titles with the greatest weekly gains.

HOT SHOT DEBUT
Where included, indicates a chart's highest-ranking new entry.

GREATEST GAINER
Where included on album charts, indicates the title with the chart's largest unit increase. Where included on airplay charts, indicates the title with the chart's largest increase in plays or audience, depending on which data the chart utilizes.

GREATEST GAINER/AIRPLAY
Where included on mixed airplay and sales charts, indicates the title with the chart's largest increase in audience.

GREATEST GAINER/DIGITAL
Where included on mixed airplay and sales charts, indicates the title with the chart's largest unit increase.

AIRPOWER
Where included on airplay charts, indicates titles appearing in the top 20 of a respective format's plays and audience rankings for the first time with increases in both plays and audience.

POWER PICK
On Dance Club Songs, indicates the title, currently below the top 20 and on the chart the week before, with the largest increase in points.

PACESETTER
Where included on album charts, indicates the title with the chart's biggest percentage growth.

HEATSEEKER GRADUATE
On the Billboard 200, where included, indicates album entered top 100 of the Billboard 200 and has been removed from Heatseekers chart.

RECURRENT RULES
Songs are removed from the Billboard Hot 100 and Hot 100 Airplay simultaneously after 20 weeks on the Billboard Hot 100 and if ranking below No. 50. Songs are removed from Hot R&B/Hip-Hop Songs after 20 weeks if ranking below No. 50.

Songs are removed from Hot Country Songs after 20 weeks if ranking below No. 10 in detections or audience, provided that they are not still gaining enough audience points to bullet or if they rank below No. 10 and post a third consecutive week of audience decline, regardless of total chart weeks.

Songs are removed from Rock Songs, Mainstream Rock, Hot Latin Songs and Latin Airplay charts after 20 weeks if ranking below No. 20.

Descending songs are removed from Adult Contemporary, Adult Top 40 and Adult R&B after 20 weeks if ranking below No. 15, after 26 weeks if ranking below No. 10, or after 52 weeks if ranking below No. 5.

Descending songs are removed from the Mainstream Top 40, Alternative, Triple A, Active Rock, Heritage Rock, Mainstream R&B/Hip-Hop, Rhythmic, Christian Songs, Christian AC Songs, Gospel Songs, Dance Airplay and Smooth Jazz Songs charts after 20 weeks and if ranking below No. 15.

CONFIGURATIONS
The following notations are viewable on certain charts in Billboard magazine: (C) CD single available. (D) Digital Download available. (M) DVD single available. (T) Vinyl Maxi-Single available. (V) Vinyl single available. (X) CD Maxi-Single available. Configurations are not included on all singles charts.

PRICING/CONFIGURATION/AVAILABILITY
Certain album charts in Billboard magazine list CD prices, which are suggested list or equivalent prices and are projected from wholesale prices.

(CD/DVD) after price indicates CD/DVD combo only available.
(+) CD/DVD combo available.
(*) indicates vinyl LP is available.

Pricing and vinyl LP availability are not included on all charts. (EX) after catalog number indicates title is exclusive to one account or has limited distribution.

AWARD CERTIFICATION LEVELS

ALBUM CHARTS
Recording Industry Assn. of America (RIAA) certification for net shipment of 500,000 albums (Gold).
RIAA certification for net shipment of 1 million units (Platinum).
RIAA certification for net shipment of 10 million units (Diamond). Numeral within Platinum or Diamond symbol indicates album¹s multi-platinum level. For boxed sets, and double albums with a running time of 100 minutes or more, the RIAA multiplies shipments by the number of discs and/or tapes.
Certification for net shipments of 50,000 units (Oro).
Certification of 100,000 units (Platino). Numeral 2 within Platinum symbol indicates certification of 200,000 units (Multi-Platino).

SINGLES CHARTS
RIAA certification for 500,000 paid downloads (Gold).
RIAA certification for 1 million paid downloads (Platinum). Numeral within platinum symbol indicates song¹s multiplatinum level.
RIAA certification for net shipment of 500,000 singles (Gold).

MUSIC VIDEO SALES
RIAA gold certification for net shipment of 25,000 units for video singles.
RIAA gold certification for net shipment of 50,000 units for short-form or long-form videos.
RIAA platinum certification for net shipment of 50,000 units for video singles.
RIAA platinum certification for sales of 100,000 units for short-form or long-form videos. Numeral within platinum symbol indicates song¹s multiplatinum level.