How long should artists be able to hold copyrights on their work? It's a question people have been debating for more than two centuries. When the British government passed a law strengthening copyright terms for authors in 1814, celebrated writers like Sir Walter Scott began making more money. A lot more.

That might sound like a good thing. Who's against artists getting rewarded for their work? But a new paper exploring the effects of that 19th-century term extension provides little support for today's extremely long copyright terms.

Britain's copyright protections once lasted for 28 years; most authors weren't expected to live much longer beyond that. Yet in 1814, Parliament agreed to lengthen the copyright term to the duration of an author's life. (If you published a work and died shortly after, your copyright would be valid for 28 years, up from 14 years.)

In the wake of that decision, according to archival documents reviewed by Megan MacGarvie, a Boston University researcher, and Petra Moser, an economist at Stanford University, writing became a much more lucrative business. After adjusting for inflation, they found:

Data on payments to authors for 208 titles between 1800 and 1829 confirm that payments to authors increased significantly after 1814. Payments to the author of the median title increased by nearly 101 percent from 83.93 pounds between 1800 and 1814 (l, converted to 1800 real terms) to 169.10l between 1815 and 1829. On average, payments to authors almost tripled, with an increase from 163.74l for 66 titles until 1814 to 494.74l for 142 titles after 1814.

The enhanced protections worked. Payments to authors rose relatively slowly in the 15 years leading up to the legislative change, and rose much faster after the fact.

So does that mean longer terms would be beneficial today? There are two reasons for skepticism. First, the new policy mainly benefited established authors. Walter Scott accounted for such a large share of the increase in earnings that the researchers had to run a separate set of calculations excluding him. After 1814, Scott's average book advance came out to more than £2,400 in 1800 pounds — 6.6 times what other authors got. Copyrights are supposed to incentivize creativity, but giving already-famous authors even larger paychecks doesn't do that.

More importantly, Britain's copyright changes took place at a time when existing terms were quite short. By contrast, authors of copyrighted works now get 70 years of protection past the end of their lives, which is far longer than the policy in Britain before 1814.

So while strengthening copyright terms made a big difference when terms were short, it's not clear that adding another few years to today's much longer terms will have the same effect.

"At extremely high levels of pre-existing rights," the authors conclude, "the incentive effects of an additional year are likely to be small. The costs of stronger copyrights in terms of limiting diffusion, however, may be substantial."