Fig. 2: Synthetic example of summary statistics to be generated and shared by data contributors.

Consider three sites, each with 1000 patients whose records contain two binary covariates, including sex (female) and age >65, and a binary outcome. Because patient‑level data cannot be shared, every site independently and simultaneously generates summary-level statistics based on all four possible combinations of the two binary covariates. Only these summary statistics are transmitted to the coordinating center.