The Formula

Two public Amazon signals go in; one number comes out. The customer rating measures quality; the review count measures consensus — how many people are standing behind that rating.

The weights are not fixed: they shift with review volume, in three tiers. The fewer reviews exist, the more the star average has to say; once tens of thousands have weighed in, the crowd is the evidence.

The Three Phases

Each product is scored in exactly one phase, decided by its review count.

Quality Phase Under 1,000 reviews

Rating 50% Volume 50%

A handful of excellent reviews counts — but cannot carry the score. With thin data, the star average leads.

Volume signal saturates at 100 reviews.

Balanced Phase 1,000 – 10,000 reviews

Rating 30% Volume 70%

The crowd has spoken. Consensus now dominates, and a lone wave of early hype can no longer prop a product up.

Volume signal saturates at 1,000 reviews.

Consensus Phase Over 10,000 reviews

Rating 10% Volume 90%

At this scale the volume signal saturates at maximum. A 4.2★ across 25,000 reviews is what the world actually receives.

Volume signal saturates at 1,000 reviews.

Worked Examples

One product, one rating — three phases. The same 4.5☆ earns a higher score as consensus grows, while the star average itself matters less and less. Every value below is computed live by the same formula the rankings use.

Product Rating → Quality Reviews → Consensus Weights PM Score
Quality Phase 4.5★ 80 reviews 9.0/10 8.0/10 50/50 8.50
Balanced Phase 4.5★ 3,000 reviews 9.0/10 10.0/10 30/70 9.70
Consensus Phase 4.5★ 25,000 reviews 9.0/10 10.0/10 10/90 9.90

Why 8.5 → 9.7 → 9.9 for the same stars? Quality contributes 4.5, then 2.7, then 0.9 — as consensus firms up, the crowd’s verdict takes over the score.

This Product’s Score

Full arithmetic for Scott Black Radial Mx Handlebar Hand Grips Fits Honda Kawasaki Suzuki Yamaha Cr80 Cr85 Cr125 Cr250 Cr500 Crf80 Crf100 Crf150 Crf230 Crf250 Crf450 Xr80 Xr100 Xr200 Xr250 Xr350 Xr400 Xr500 Xr600 Xr650 Kx60 Kx65 Kx80 Kx85 Kx100 Kx125 Kx250 Kx500 Kx250f Kx450 Klx110 Klx125 Klx140 Klx250 Klx300 Kdx200 Kdx220 Rm65 Rm80 Rm85 Rm125 Rm250 Rmz250 Rmz450 Dr200 Dr250 Dr350 Drz110 Drz250 Drz400 Yz80 Yz85 Yz125 Yz250 Yz250f Yz450 Yz490 Wr250 Wr450 Ttr90 Ttr110 Ttr125 Ttr230 Ttr250 Yz400 Yz426, recomputed live from current data.

7.0 PM Score
Balanced Phase · 1,000 – 10,000 reviews SCOTT · ASIN B00GQ01NXQ
Quality — customer rating 0.0★ → 0.0/10
Consensus — review volume 1,641 reviews → 10.0/10

0.0 × 0.3 + 10.0 × 0.7 = 7.00

View this product on Amazon

What We Never Score

Price never enters it

A $19 kettle and a $190 kettle face the identical rubric. Price is a purchase decision, not a quality signal — and Amazon prices move too fast to score against.

Only public signals

Both inputs — star rating and review count — come from Amazon’s own public data. Nothing proprietary, nothing self-reported by brands.

One formula for all

The same equation scores every product on the site, with no per-brand overrides, no manual boosts, and no exceptions — including the ones on this page.