Formalistic data and code availability policy in high-profile medical journals and pervasive policy-practice gaps in published articles: A meta-research study

Poor data and code (DAC) sharing undermines open science principles. This study evaluates the stringency of DAC availability policies in high-profile medical journals and identifies policy-practice gaps (PPG) in published articles. DAC availability policies of 931 Q1 medical journals (Clarivate JCR 2021) were evaluated, with PPGs quantified across 3,191 articles from The BMJ, JAMA, NEJM, and The Lancet. Only 9.1% (85/931) of journals mandated DAC sharing and availability statements, with 70.6% of these lacking mechanisms to verify authenticity, and 61.2% allowing publication despite invalid sharing. Secondary analysis revealed a disproportionate distribution of policies across subspecialties, with 18.6% (11/59) of subspecialties having &gt;20% journals with mandated policies. Journal impact factors exhibited positive correlations with the stringency of availability statement policies (ρ = 0.20, <i>p</i> &lt; 0.001) but not with sharing policies (ρ = 0.01, <i>p</i> = 0.737). Among the 3,191 articles, PPGs were observed in over 90% of cases. Specifically, 33.7% lacked DAC availability statements, 23.3% refused sharing (58.4% of which without justification in public statements), and 13.5% declared public sharing, with 39.0% being unreachable. Finally, only 0.5% achieved full computational reproducibility. Formalistic policies and prevalent PPGs undermine DAC transparency, necessitating a supportive publication ecosystem that empowers authors to uphold scientific responsibility and integrity.