Where our figures come from
A figure you cannot trace is a figure you cannot check. Every price, cost and estimate on this site is stored with where it came from and when it was last verified, and both are shown next to it.
The order we prefer sources in
Not every source is equally reliable or equally legitimate to use, so we work down this list rather than taking whatever is easiest to obtain.
- Licensed data feeds, first. Retailers publish product feeds through affiliate networks specifically so that sites like this one can use them. The data is accurate, it is refreshed daily, and we are licensed to use it. This is where prices come from.
- The manufacturer’s own published pages, second. Specifications, release dates, security update histories and support status come from the people who made the device, cited with the page and the date we read it.
- Manual entry against a named source, third. Repair prices and similar figures that no feed carries, entered by a person who records where it came from, with a date. These are re-checked on a schedule, and a figure that has gone stale lowers the confidence of anything that uses it rather than silently continuing to look current.
- Anything else, last and narrowly. Where we fetch a page, we identify ourselves honestly, we respect the site’s robots file and its terms, and we take only what we need. No single unlicensed source is ever the only support for something the site depends on.
What we do with an offer we are not sure about
Matching a row in a retailer’s feed to the exact device it describes is the hardest part of ingesting price data — storage sizes, model years and condition grades are written differently by every shop. Where the match is confident we record it. Where it is not, it goes to a person to decide.
It is never guessed. A wrong match publishes one device’s price against another, and because the price history is append-only that mistake is permanent — it stays in the statistics long after the listing has gone. So an uncertain match shows nowhere on the site and enters no average until somebody has confirmed it.
Verification dates are shown, not stored quietly
Each figure carries the date it was last checked against its source, and pages show it. Where something is older than we are comfortable with, the page says so and the answer that depends on it is marked less confident. We would rather tell you a figure is four months old than let you assume it is current.
The per-figure list
This page describes the policy. The full list of individual sources — every page, feed and document behind every published figure, with its date — is generated from the database and published here as each part of the catalogue goes live, rather than hand-written and left to drift out of step with what the site is actually using.
Tell us if something is wrong
If a figure here does not match what you can see at the source, we want to know. Contact us — a correction is more useful to us than being right about the rest.