Pollock's Term - 14 Years

Nate Anderson of Ars Technica summarizes a recent paper on copyright length as follows:

It's easy enough to find out how long copyrights last, but much harder to decide how long they should last—but that didn't stop Cambridge University's Rufus Pollock from using economics formulas to answer the question. In a newly-released paper, Pollock pegs the "optimal level for copyright" at only 14 years.

Rufus Pollock, a Cambridge doctoral candidate, has applied economics
tools (factoring in decline of production and reproduction costs) to
calculate optimal copyright term.
The Value of the Public Domain is available at the Institute for Public Policy Research. Pollock's work was presented at the 2007 Society for Economic Research on Copyright Issues (SERCI) Congress this week.