2017 State of DevOps Report
https://dora.dev/research/2017/2017-state-of-devops-report.pdf
Method
"This year we conducted additional analysis to see if there is evidence for performance differences correlating to trunk-based development practices. We investigated how long branches and forks live before being integrated into master, and how much time it takes to merge and integrate the code on them."
Population
"Our target population for this survey was practitioners and leaders working in, or closely with, IT, and especially those familiar with DevOps... we used snowball sampling to obtain respondents."
What it does not show
Branch lifetime is a self-reported categorical answer, not measured from git history — the report notes practitioner scepticism it does not resolve with repository data. No mechanism is isolated: loosely coupled architecture and strong automated testing correlate with trunk-based development in the same model and may be doing the work, with short branches a symptom rather than a cause.
Nicole Forsgren, Jez Humble, Gene Kim, Alanna Brown, Nigel Kersten
Teams that merge to trunk at least daily, keep branch lifetimes under a day, and maintain fewer than three active branches report higher delivery performance, with the difference stated as statistically significant and replicated across two consecutive years: high performers’ branch life and integration typically last hours, low performers’ days.
Tier II: Same cross-sectional self-report design as the 2019 report, with a specific branch-lifetime analysis. Self-reported, no control group.