So How'd We Keep Score?

In an industry notorious for its payola scandals, dodgy bookkeeping, and rampaging egos, divining the 25 best-selling albums of all time is a true challenge. While the No. 1 standing of Thriller is virtually indisputable, figuring out what comes after that and why is one of pop culture's great parlor games. As such, some questions begged to be asked:

1. Exactly how did ENTERTAINMENT WEEKLY come up with its Top 25?
Our list is based on statistics provided by two of the more reliable record keepers in the music business — the Recording Industry Association of America (RIAA) and Billboard magazine. The Top 25 was calculated by Billboard for EW using sales figures from the RIAA. Those numbers were further quantified with data (the number of weeks an album held the No. 1 spot, plus chart longevity) from Billboard's Top 200 pop album chart.

2. What is the RIAA and where does it get its numbers?
The RIAA is the U.S. record industry's trade organization. One of its functions is to issue gold (500,000 albums sold) and platinum (one million albums sold) certification awards. These sales figures represent albums sold through retailers, record clubs, and direct-mail accounts. For an album to receive gold or platinum certification, a record company must submit figures to the RIAA (which are then audited by an independent accounting firm). Membership in the RIAA and the submission of records for certification, however, are entirely voluntary. For example, Motown didn't open its books to the RIAA in the '70s, which may explain the absence of Stevie Wonder's Songs in the Key of Life from our list. Songs was No. 1 for 14 weeks in 1976 — far longer than either of the Eagles albums included here — but there's just no independent way of determining how many copies it sold. Another problem with RIAA numbers is that not every record company bothers to get up-to-date certification on its older titles — especially those by artists who no longer record for the label. Because the King of Pop likes to keep his crown untarnished, Sony Music can be counted on to make sure Michael Jackson receives recognition whenever he reaches a new multi-platinum plateau.

3. Where's Sgt. Pepper's?
A lot of older superstars aren't on this list, primarily because the growth of the record market has helped catapult, say, Whitney Houston and Garth Brooks past the likes of the Beatles and the Stones. In 1962, the soundtrack to West Side Story hit No. 1 and stayed there 54 weeks — four months longer than Thriller. But at that time, total industry sales were under $1 billion. They're now almost 40 times that figure. It pays to be a big fish in a big pond.

That said, older Billboard chart-toppers do have one distinct advantage. The repeat purchase on CD of, for example, the Eagles' '76 greatest-hits album, a disc initially released on vinyl, in part accounts for its astonishing 22 million tally. Similar back-catalog artists are guaranteed continued sales monitoring (and royalties) thanks to SoundScan, the electronic retail accounting system, introduced in 1991, that has helped stem decades of suspect record-company bookkeeping. (By the way, Sgt. Pepper's currently sits at No. 45 on the list of all-time best-sellers.)