A Dual Model of Open Source License Growth

TL;DR

This paper analyzes ten years of open source projects to understand how license choices impact project growth, revealing a shift from restrictive to permissive licenses around 2001.

Contribution

It introduces analytical models linking license types to project growth and documents a significant shift in license preferences over time.

Findings

Reversal from restrictive to permissive licenses around 2001

Analytical models explaining license choice impact

Correlation between license type and project growth

Abstract

Every open source project needs to decide on an open source license. This decision is of high economic relevance: Just which license is the best one to help the project grow and attract a community? The most common question is: Should the project choose a restrictive (reciprocal) license or a more permissive one? As an important step towards answering this question, this paper analyses actual license choice and correlated project growth from ten years of open source projects. It provides closed analytical models and finds that around 2001 a reversal in license choice occurred from restrictive towards permissive licenses.