Every R3 category is scored on its own published, dated weighting system. This page lists those systems, the exact weights behind every score, and the record of every time we have revised one.
The short version
R3 versions its scoring like software. Each of 81 product categories is scored on its own weighting system with a version number and a fixed activation date, and there are 35 distinct weightings across them because what matters differs by product. Scores are absolute, not curved: every product in a category is measured against the same fixed weighting, regardless of price. When evidence justifies a change, we publish a new version with the reason. So far 1 category has been revised.
Categories whose scoring system we have changed since launch. Each entry shows what changed and why, with the old version retired and dated.
Increased efficacy weight (30->35%) because NSF certifications (P473, 53, 401) are the primary differentiators for PFAS and lead removal. Reduced usability (10->7%) and removed suitability (2->0%) since modern filters meet basic usability standards and suitability factors are covered by efficacy.
The scoring system in force today for each category, with its version, activation date, and the full pillar weighting behind every score.
A note on what this page does and does not show. It shows the versioned, dated weighting behind every category score and the full history of any category we have revised. It does not yet list individual products whose scores moved when a weighting changed; we are building that record and will add it here as it accumulates, rather than reconstruct it after the fact.