Methodology
How we decide that two offers are the same product, where prices and specifications come from, and what we never do. It describes what the code does today: if the code changes, this page changes.
Where offers come from
From the catalogues shops publish through affiliate networks (Awin, Tradedoubler and others), from Kelkoo and from eBay. We read them several times a day. Every offer keeps the time we read it and expires: after that it is no longer shown, even if a product is left with no prices.
When two offers are the same product
We only match automatically in two cases:
- By EAN barcode, after checking its check digit. The same code written with or without leading zeros is the same code.
- By exact brand and model code, when the shop is not a marketplace, the title does not describe a kit, a bundle, a spare part or an accessory, and the price is between half and 1.6 times the product's reference (the brand's official shop price or, if there is none, what the other shops ask).
Offers from marketplaces, where anyone can sell, and similarities worked out by software are never joined on their own: they stay as a proposal and a person decides whether they are the same product. We never join two offers just because their titles look alike.
An offer whose price falls outside that range is neither hidden nor accepted: it is set aside for review, because it is usually a different product, a different version or a catalogue error.
Prices
We show the total price: product, tax and shipping. If the shop does not say what shipping costs, we say so instead of guessing, and that offer cannot carry the "Cheapest" label: only the offer that is cheapest with everything added up, against all the others, carries it.
We keep every price change from the day we start following an offer. Charts come from that history, and a discount is only announced when it beats the lowest price of the previous 30 days.
Product data
Specifications come from the manufacturer's documentation, with the link and the date it was read. If the manufacturer does not give a figure, the gap stays empty and we say so. Written verdicts are signed by a person and only discuss what is in the specification.
Clicks
Clicks from bots and browser prefetches are not sent to the shop and do not count in our figures. We only count visits by people.
What we do not do
- We do not charge shops to be listed or to be listed higher.
- We do not give scores or stars, and we do not claim to have tested what we have not tested.
- We do not show an expired price as if it were current.
- We do not fill a missing figure with an estimate.