We searched a variety of software and code licenses in PubMed to discover which are most commonly used by the biological, medical, and life sciences communities. The five with the most citations were Apache, BSD, Creative Commons, GNU, and the MIT/X11/MIT-X License. Links to more information on each of these licenses is given below, with brief descriptions.
Choosing a license for your software can be a very personal decision. Each of these popular licenses has adherents who swear by it and opponents who dislike them, sometimes intensely. We recommend that you not rely solely on the information in this Guide for making your decision, but consider consulting an expert in this area. Many academic institutions provide services to support their faculty and staff in these decisions, such as the University of Michigan's Copyright Office, Office of Technology Transfer, and UM General Counsel Research and Intellectual Property/Information Technology Group.
As background for these conversations, you may wish to explore GitHub's "Choose A License" resource: https://choosealicense.com/.
For a more comprehensive list of open source software licenses, refer to the License List from the Linux Foundation Collaborative Projects' Software Package Data Exchange (SPDX).
"These licenses help us achieve our goal of providing reliable and long-lived software products through collaborative open source software development. In all cases, contributors retain full rights to use their original contributions for any other purpose outside of Apache while providing the ASF and its projects the right to distribute and build upon their work within Apache."
BSD (Berkeley Source Distribution)
Developed at the University of California, Berkeley, and first used in 1980, BSD remains a popular and simple license to use for software and code projects developed with the intention of being shared widely. The original license has evolved into a variety of formats and flavors, including but not limited to BSD 3-Clause "New" or "Revised", BSD 2-Clause "Simplified", FreeBSD, NetBSD, Lawrence Berkeley National Labs BSD variant license (LBL example) (BSD-3-Clause-LBNL or LBNLBSD), OpenBSD, and others.
"The Creative Commons copyright licenses and tools forge a balance inside the traditional “all rights reserved” setting that copyright law creates. Our tools give everyone from individual creators to large companies and institutions a simple, standardized way to grant copyright permissions to their creative work. The combination of our tools and our users is a vast and growing digital commons, a pool of content that can be copied, distributed, edited, remixed, and built upon, all within the boundaries of copyright law."
"We recommend against using Creative Commons licenses for software. Instead, we strongly encourage you to use one of the very good software licenses which are already available. We recommend considering licenses made available by the Free Software Foundation or listed as “open source” by the Open Source Initiative."
Ironically, if you explore the resources the Creative Commons organization recommends for software liscencing, you may find yourself directed back to Creative Commons. This means that despite concerns in the use of Creative Commons licenses for software and code project, you still may discover projects that depend on this popular license format.
GNU General Public License (GNU GPL) and GNU Free Documentation License (GFDL)
"The GNU General Public License is a free, copyleft license for software and other kinds of works. The licenses for most software and other practical works are designed to take away your freedom to share and change the works. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change all versions of a program--to make sure it remains free software for all its users. We, the Free Software Foundation, use the GNU General Public License for most of our software; it applies also to any other work released this way by its authors. You can apply it to your programs, too."
The most common name for this license is probably the "MIT License," however, as you can see, there is considerable difference of opinion about what is the best name for this popular license. Because the MIT License is not copyrighted, there are also a variety of permutations and variations in which people have customized the license to suit their purposes.