How the numbers are made

Five rules every published number follows

1. It is live. Nothing is typed in. A figure is queried from the catalogue and cached for at most an hour, so a page cannot drift from the data it describes.
2. It carries its sample. Hover any dotted number and it tells you how many domains, offers or publishers it rests on and when it was measured. Under a floor, a figure is withheld rather than published small.
3. It names its method. Each number points at one of the four methodology pages below. Change the method and the version on every page changes with it.
4. It names no supplier and no domain. Suppliers are grouped by how they operate; publishers appear as shares, medians and counts, never as a list, not even as examples. The only domains we name publicly are the top-ranking sites of a topic, which are public by definition. Data sources are described by what they measure, not named.
5. Observed is not caused. Anything measured after a placement (rank movement, traffic) is reported as what happened, never as what the link did.

The methods

• Data sources

  Where every number comes from: the marketplaces, the backlink index, the web graph, our own orders.

• Quality methodology

  The five tests behind “suspect”, what they catch, what they miss, and the Placement Score built on them.

• Pricing methodology

  How prices are normalised, what “price gap” and “market reference” mean, and what they do not.

• The web graph

  The open web graph: saturation, leader links, probable buyers, and its limits.

• Backlink Price Index

  A monthly, immutable, fixed-basket index of what link placements cost, with CSV.

Citing a figure

Link to the page and quote the number with its date; the page will have moved on by the time a reader follows the link, and that is the point. Every research page also publishes its figures as schema.org Dataset markup, each variable carrying its value, unit, sample and method URL, under CC BY 4.0. Where you need a fixed number, the API returns the same measurements per domain at request time.

Changes

2026-09-05: first versioned publication of the methods. Placement Score v1 and the market reference price added to the API; both documented here rather than presented as verdicts.