The protection of copyright law is essential for creative endeavors. It keeps people from simply copying your song, play, novel, TV show, movie or other creative work. That, in turn, makes it easier to profit from performing your work, since only you or the people you license can perform it. It also encourages creators to take risks, because success could be lucrative.

In America today, copyright protection for works created after Jan. 1, 1978, typically lasts for the lifetime of the creator plus 70 years. Works created in the U.S. before 1924 are now in the public domain, meaning they have no copyright protection. Works created in the U.S. before 1978 but after 1924 are generally protected for 95 years from their first date of publication. There are different standards because Congress changed the law.

The period of copyright protection is not an immutable law of nature, and copyright law varies between countries. Congress can and has chosen to extend the period from time to time. Indeed, protecting copyrights for the creator’s lifetime plus 70 years was a sticking point in the negotiations for the Trans-Pacific Partnership.

Why don’t we protect copyrights forever? There are several good reasons. One is that, over time, it would become increasingly difficult to locate the owner, if the copyright were handed down to descendants. This could result in litigation by competing heirs.

Another reason is that allowing copyrights to expire promotes new creative work in the long run. This is because beloved stories and characters enter the public domain after the term of copyright protection ends. That allows new artists and creators to reuse and update those characters and stories in new works. In this way, the expiration of copyright keeps our culture’s favorite creations alive for new generations.

If we never let copyrights expire, the public — and the work itself — could lose out. If we didn’t have copyright protections at all, there would be little financial incentive to create. So what length of protection would best promote creativity while protecting creators’ financial interests?

A group of economists recently examined the history of opera in Venetia (Venice) to try to find a concrete answer to that question.

Copyright protection spread from France to Italy with Napoleon

The economists dug into the records of 2,598 operas created in Italy between 1770 and 1900. Before 1801, when Napoleon brought French copyright law into northern Italy, the Italian states created about 14 new operas each decade, with Venetia producing slightly less. After copyright law was introduced, the region began creating as many as 34 new operas per decade and Venetia, along with Milan, became a world leader in opera composition

In other words, the introduction of copyright law into northern Italy increased opera production by 150 percent. Napoleon’s copyright term was the life of the creator plus 10 years

The region eventually lengthened the copyright term to life plus 30 years, then life plus 40 years. The economists who examined this period found that, when the protection term was life plus 40 years, however, the creation of new operas began to decline

The results of the economists’ research could indicate that America’s current term of copyright protection could be too long. It could be weighing too much on the side of original content creators and not enough on the side of the public and those who wish to reuse or update the work.

How long do you think copyright protection should last?