How the Waterlyst Score works

The Waterlyst Score is an editorial score, not a customer review. For a product it starts from a Bayesian-weighted blend of the ratings that exact model has received across the marketplaces that sell it — Amazon, eBay, Walmart, Home Depot, AliExpress and other marketplaces — pooled into one figure, and moves toward the ratings Waterlyst users give as they add up. Services start from ratings published on sites such as Google. Companies are rated on their own scale (see below). Every score page lists the marketplaces and sources it uses, with a link where one is available, and shows Waterlyst user ratings separately.

Published ratings are converted to a common 0–5 scale and pooled across marketplaces, weighted by how many ratings each reports. That starting point counts as at most 10 ratings, however many the marketplaces have, so Waterlyst users can genuinely move the score:

Score = (starting point × its weight + sum of Waterlyst ratings) ÷ (its weight + number of Waterlyst ratings)

With 10 Waterlyst ratings, users and published sources count equally; after that, users count more. Products and services are shown out of 10 (the 0–5 score doubled), with water drops.

Company ratings are a separate scale from product and service scores. A company is shown out of 5, as stars, based on the ratings Waterlyst users give it plus any published ratings from other sites that we list on the company page. Waterlyst user ratings are always shown separately.

• Each published rating records when it was last checked. Its weight halves every year since that check, so outdated figures fade out unless we confirm them again.
• Figures collected before we recorded sources are marked “source check in progress” and stop counting after 90 days unless we record where they come from.
• With no published ratings and no Waterlyst ratings, we show no score at all.

• We do not create ratings or present published ratings as Waterlyst user ratings.
• We do not accept payment for a score. Suppliers cannot edit their own ratings or sources.
• Only ratings from Waterlyst users are shared with search engines as review data; the blended Waterlyst Score is not.

Signed-in visitors can rate once per product, service, company, expert or course. If you think a published source is wrong or out of date, let us know through our contact page.