CROSS-RCT is a reporting guideline intended to improve the completeness, transparency, and reproducibility of reporting of sample size determination in randomized controlled trials (RCTs). It focuses on what information should be reported to enable readers, reviewers, editors, and methodologists to understand how the planned sample size was determined and to assess whether the calculation can be reproduced from the information provided.
The guideline covers key components of sample size determination, including the statistical framework and trial design, outcome assumptions, target difference or non-inferiority/equivalence margin where applicable, significance level, statistical power, allocation ratio, assumptions concerning variability or event rates, adjustments for attrition and design features, the resulting sample size, and the sources used to justify key assumptions. It also provides reporting considerations for alternative approaches to sample size determination, including precision-based, feasibility-based, and Bayesian approaches, where applicable.
CROSS-RCT is intended as a reporting rather than methodological or critical-appraisal guideline: it does not prescribe how sample size should be calculated or judge whether particular assumptions are statistically or clinically correct. Existing guidance, including CONSORT, SPIRIT, and DELTA2, provides important recommendations concerning sample size determination and its reporting, but does not provide a comprehensive, operational, item-level reporting framework covering the information required to understand and reproduce sample size determinations across different approaches. CROSS-RCT is therefore designed to complement, rather than replace, existing guidance by providing explicit reporting items and decision rules specifically focused on the transparent and reproducible reporting of sample size determination in RCTs.
Registered: 28 October 2026
Last updated:
Contact: Yinghui Jin Email: [email protected]