Open source software: Motivation and restrictive licensing

TitleOpen source software: Motivation and restrictive licensing
Publication TypeJournal Article
Year of Publication2007
AuthorsFershtman, C, Gandal, N
Secondary TitleInternational Economics and Economic Policy
PublisherSpringer Berlin / Heidelberg
ISSN Number1612-4804
Other Numbers10.1007/s10368-007-0086-4
Keywordscontributions, contributors, developers, incentives, license analysis, licenses, lines of code, loc, MOTIVATION, restrictive, scm, size, status, version history

Open source software (OSS) is an economic paradox. Development of open source software is often done by unpaid volunteers and the source code is typically freely available. Surveys suggest that status, signaling, and intrinsic motivations play an important role in inducing developers to invest effort. Contribution to an OSS project is rewarded by adding one’s name to the list of contributors which is publicly observable. Such incentives imply that programmers may have little incentive to contribute beyond the threshold level required for being listed as a contributor. Using a unique data set we empirically examine this hypothesis. We find that the output per contributor in open source projects is much higher when licenses are less restrictive and more commercially oriented. These results indeed suggest a status, signaling, or intrinsic motivation for participation in OSS projects with restrictive licenses.


"We employ a unique data set consisting of 71 open source projects hosted at the SourceForge web site. The 71 projects in the sample were chosen (in January 2000)"
"This sample was observed over an 18-month period from January 2002 through the middle of 2003, with data collected at 2-month intervals."
"We are grateful to NERA for providing us with the data."
"Although we only have data on a relatively small sample of the projects hosted SourceForge, the sample is unique because of data on lines of code as well as data on different versions of the program. The latter is a potentially important control variable, since a change in version may necessitate additional lines of code.
Our data set contains information on the size of the open source projects in the form of source lines of code (SLOC). Using SLOC as a performance measure is not always ideal; nevertheless, this performance measure is employed in the profession and the literature.15 For our purposes, SLOC is in fact an ideal measure, because we want to measure the effort that is put into the project, rather than whether a project succeeds."

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