Maintaining a Pareto pool that retains every candidate which wins on even a single training example — rather than keeping only the single best candidate — is responsible for more than half of GEPA's performance gains, doubling standard optimization-loop performance.
Standard evolutionary/optimization loops collapse to the current best and stall in local optima; a Pareto retention rule preserves specialists that later aggregate into a stronger general solution, which is a cheap and general fix to a ubiquitous failure mode.
Any iterative search over candidates (prompts, code, configs, agent topologies) evaluated on a heterogeneous example set should retain Pareto-non-dominated candidates rather than a single global best.
A Pareto pool retains every candidate that wins on even one training example.
Over four benchmarks, Pareto-based candidate selection accounts for more than half of GEPA's performance gains, doubling standard loop performance.