SurrogateRank is an R package that uses rank-based nonparametric approaches to evaluate surrogate marker(s) in a small sample size setting.
More details on the method are available in Parast L, Cai T, Tian L (2024). A Rank-Based Approach to Evaluate a Surrogate Marker in a Small Sample Setting. Biometrics, 80(1): ujad035, doi:10.1093/biomtc/ujad035.
This approach was also extended to the high-dimensional setting. Details are described in Hughes A, Parast L, Thiébaut R, Hejblum BP (2025). RISE : Two-Step Rank-Based Identification of High-Dimensional Surrogate Markers Applied to Vaccinology. Statistics in Medicine, 44(20-22): e70241, doi:10.1002/sim.70241.
Finally, these approaches were extended to the multi-trial setting using meta-analysis. Details are described in the preprint Hughes A, Parast L, Thiébaut R, Hejblum BP (2026). Meta-Analysis of High-Dimensional Surrogate Markers. arXiv, arXiv:2605.03819.
Go here to view a tutorial for this package: SurrogateRank Tutorial. We also have a shiny app implementing these methods here.