U.K. authors' and composers' collecting society PRS for Music has published a report showing new research into file-sharing over a 12-month period that casts doubt on the long tail theory.

Will Page, chief economist at PRS for Music, teamed up with industry analyst Eric Garland of BigChampagne to publish the paper "The Long Tail of P2P." The original theory was proposed by Chris Anderson in Wired magazine in 2004 and expanded in the book "The Long Tail: Why the Future of Business Is Selling Less of More."

The Page and Garland' research involved analysis of billions of swaps on a 12-month global file-sharing data set and - in contrast to the long-tail theory - they found "a very hit-heavy, skinny tail profile" where 95% of the inventory accounted for only 20% of swaps on P2P. They also contend that P2P activity mirrors the legal download market to some extent.

"What continues to fascinate me about our prior Radiohead 'In Rainbows, On Torrents' study was the simple fact that after proving popular on torrents, 'In Rainbows' also proved popular in legal markets and even reached No. 1 on iTunes," said Page. "This study helps explain that phenomenon, and allows PRS for Music to understand an illegal digital market for music that's been with us for longer and is far larger than the legal one. By doing so, it helps move the PRS for Music forward with the challenge of monetizing it on behalf of our songwriters."

Eric Garland, chief executive at BigChampagne, added: "There are many broad and pronounced differences between file-sharing networks and the local record shop, or iTunes store. But the most popular artists, albums and songs tend to dominate the charts everywhere. BigChampagne has yet to see a big hit or wildly popular release in the pirate market that was not also a top seller in the licensed market."

"The Long Tail of P2P" was launched at the Great Escape music convention in Brighton today (May 14) and is available at prsformusic.com/economics to download.

The report states that on average the most popular files were swapped over 14 million times over that one-year period. And the most swapped files were also the most downloaded on legal music sites.

More than 13 million unique files found at least one swap via P2P, according to the research.

Success in the courts against piracy has not dampened illegal P2P activity either, the report says. Despite the conviction against the Pirate Bay operators in Sweden last month, Lady GaGa's "The Fame" was downloaded 388,000 times in the last week of April 2009 alone.