How we score and earn
What a board is
A board ranks one kind of product, for example cordless drills under £100. For each product we record, on one date, what the store shows: the star rating, the number of reviews, and the price. For Amazon we record them by hand. For shops on the Awin network the figures come from the product feed the shop publishes for its affiliates, which is meant for exactly this. The date and the store are printed at the top of the board.
The score
A star rating on its own misleads. Three reviews averaging 5.0 say less than eight thousand averaging 4.6, but a plain list of ratings would put the first one on top.
So each product's score is its rating weighed by how many people left one. It is a Bayesian average, the same idea film sites use for their top lists:
score = (v ÷ (v + m)) × R + (m ÷ (v + m)) × C
| Symbol | What it is |
|---|---|
| R | The product's star rating |
| v | How many reviews it has |
| C | The average rating across the products on the board |
| m | How many reviews it takes before a product's own rating counts for more than the average. We use 250 unless a board says otherwise |
A product with thousands of reviews keeps almost exactly its own rating. A product with a handful is pulled towards the board's average until it has earned more.
Who is left off
Anything with fewer reviews than the board's minimum (normally 50) is not ranked at all. It is listed under the board, with its rating and review count, so you can see what was left off and why.
The picks
Three picks sit at the top of each board, and each is worked out from the same figures rather than chosen:
- Best overall: the highest score on the board.
- Best budget: the highest score among the cheaper half of the board.
- Most reviewed: the product the most buyers have rated.
One product can hold more than one pick.
What the listing says, and what buyers mention
Each product has two panels side by side.
- What the listing says is the seller's own claims, taken from the product page. They are the seller's words, not ours, and we do not vouch for them.
- What buyers mention is our summary of the reviews we read: what buyers praise and what they complain about. It says how many reviews were read and when. We summarise in our own words and never quote a review.
The claim check
Where a listing makes a claim that buyers talk about, we set the two side by side and give one of three verdicts:
| Verdict | What it means |
|---|---|
| Holds up | Buyers' reports agree with the claim |
| Mixed | Some buyers agree and some do not |
| Disputed by buyers | Buyers commonly report otherwise |
A verdict is about what buyers report, not a test of our own. It is only as good as the reviews it summarises, which is why each panel says which reviews they were.
Test scores
Where shops do not publish their customers' ratings, as with tyres, a board is ranked by independent tests instead: ADAC, Auto Bild and the other publications that test products under controlled conditions and print every result.
Each test counts as the share of its field the product beat: first place is 100, last is 0, and 3rd of 16 is 87. A product's test score is the average of its tests together with one middle score of 50. That extra 50 means a product that did well in two tests outranks one that did as well in only one, and no single test can carry a product to the top alone.
Every test is listed on the card with its size, its placing and a link to the report, so you can check the working. Tests are in different sizes and years; a tyre's result in one size is a good guide to the same tyre in another, not a guarantee. No shop or maker pays for a place, and the shop links beside each product earn us a commission whichever one you choose.
Prices
Shown as bands, such as £50–75, not exact figures. Prices change daily and the store's terms do not allow us to show its prices except through its own live feed. Check the current price on the store before you buy.
How these pages earn
As an Amazon Associate I earn from qualifying purchases. Links to other shops, such as Machine Mart and Tyres UK, are affiliate links through the Awin network, and earn a commission from that shop. Every ranking page carries a small "Ad" label at the top that links here, and the same wording is in the footer of every page. Those boards also offer "Compare on Amazon" beside each product: it opens Amazon's own search for that product, and we may earn from Amazon if you buy there. The ranking still comes only from the shop's own customer ratings. If you buy through a link here we may earn a commission, at no cost to you.
- It never changes a score. The method above is the whole of it.
- Nobody pays to be on a board, and we do not accept free products in return for a place.
- The links are marked as sponsored for search engines, and every page is labelled "Ad" at the top.
- No widgets or scripts from any shop. The shop sees our tag only when you click a link.
- Product photos come from the shops' affiliate feeds, served by Awin for exactly this use, or are ours or licensed. Where there is none, the page shows a drawing of the kind of product.
What we do not claim
We have not tested the products on a board unless the board says so. The scores summarise what the store's customers said; they are not our review of the product. Some boards have a video version, presented by Gaffer, an AI-voiced cartoon host. He reads out the same figures; he has not used the products either.
Corrections
If a figure on a board is wrong or out of date, email hello@oneappcompany.com with the board and the product, and we will check it and change the date.