They characterize simple rules—including uniform, mean-proportional, and covariance-based linear rules—by formal properties like reshuffling, source-anonymous contributions, and aggregate contributions. The framework also defines broad rule classes and introduces scenario-based rules for settings where probabilistic modeling is impractical. However, groups often start by agreeing on principles; for example, protecting participants’ information, avoiding punitive allocation processes, and aiming for equitable sharing, rather than on a specific mathematical rule. This raises an important question: which risk-sharing rule is implied by a chosen set of principles—and what principles are implicitly endorsed by choosing a given rule? For instance, they established that equal sharing (the uniform rule) is singled out by combining reshuffling with source-anonymous contributions.

Source: The Herald March 12, 2026 19:31 UTC