Michael Hilton, Timothy Tunnell, Kai Huang, Darko Marinov, Danny Dig (Oregon State University, University of Illinois) · 2016
Hilton et al. (2016) analyzed 34,544 open-source projects from GitHub and found that 40% of all projects in their breadth corpus use CI. The study also surveyed 442 developers and analyzed 1.5M builds from Travis CI, finding that CI is widely adopted by the most popular projects and that CI adoption was growing over time.
Why read: Primary source for the 40% CI adoption figure; foundational study that established the empirical baseline for CI adoption research.
Researchers from University of Mons (Belgium) and Radboud University (Netherlands) · March 2026
Large-scale empirical study of GitHub Actions workflow evolution across 49K+ repositories (267K+ workflow histories) from 2019-2025. Cites Decan et al. (2022) finding that GHA had achieved a 43.9% adoption rate in a dataset of 68K GitHub repositories by January 2022.
Why read: Most recent large-scale CI adoption study; provides 2022 GHA adoption data (43.9%) and evidence on dependency update tool usage (Dependabot 69.2%, Renovate 21.0%).
JetBrains TeamCity and Research departments · October 6, 2025
JetBrains CI/CD survey of 805 participants found 62% use GitHub Actions for personal projects and 41% in organizations. Jenkins and GitLab remain heavily used in enterprises.
Why read: Provides developer survey perspective on CI/CD tool usage complementing the repository-mining studies.