Open Science Policies and Practices Among Medical Journals

Importance: Open science practices are essential for improving transparency, reproducibility, and trust in biomedical research. Journals play a critical role in promoting these practices through editorial policies, yet implementation and impact remain unclear. Objective: To evaluate the open science policies of leading medical journals and assess implementation and detectability of practices using automated tools. Design, Setting, and Participants: This cross-sectional study of journal policies and open science practices evaluated research articles published in 10 leading general medical journals from January 2020 to December 2023. Additionally, the diagnostic accuracy of automated tools was validated against manual extraction. Exposures: Journal policies regarding open science practices and article-level implementation of 13 core practices including registration, protocol sharing, and intention to share data. Main Outcomes and Measures: Journal policies were assessed using the Transparency and Openness Promotion guidelines (TOP2025). At the article level, 13 core open science practices were examined. Additionally, 9 validated automated tools were applied to detect these practices, and their performance was compared with manual extraction of articles. Results: Overall, 15 624 research articles published in 10 general medical journals were analyzed (validation subset, 312 articles: 103 randomized clinical trials [RCTs], 98 meta-analyses, and 111 with other designs). At the journal level, TOP2025 evaluation identified substantial heterogeneity in policies, primarily applied to clinical trials. At the article level, open science practices were more frequently implemented in RCTs than other designs: registration (RCTs: 99% [95% CI, 97%-100%]; meta-analyses: 69% [95% CI, 56%-79%]; other designs: 16% [95% CI, 9%-26%]), protocol sharing (RCTs: 96% [95% CI, 93%-98%]; meta-analyses: 67% [95% CI, 54%-78%]; other designs: 20% [95% CI, 12%-33%]), and intention to share data (RCTs: 79% [95% CI, 67%-87%]; meta-analyses: 65% [51%-77%]; other designs: 70% [95% CI, 57%-81%]). Automated tools showed variable performance (F1 scores, 0.06-1.00) and generally underestimated practices. Conclusions and Relevance: In this cross-sectional study of 15 624 articles in 10 leading medical journals, journal policies were only partially aligned with TOP2025, and article-level open science practices were more frequently reported for RCTs than for other designs, supporting the need for stronger journal policies.