Method

Every book on this shelf makes one promise: every claim has a source, every source has a date, and you can check both. This page explains how we hold to it.

How we choose sources

We use four kinds of source, in this order of preference:

1. Platform documentation from the companies that run the systems we write about. These describe how products are meant to work.
2. Original research with a published method: research centres, academic papers, and studies that state their sample, dates and definitions.
3. Large vendor datasets. Many useful studies come from companies that sell marketing tools. We use them, and we name the vendor every time.
4. Trade press reporting a study, only where the original is not public. We name the publication and the original source.

We do not use anonymous statistics, numbers we cannot trace to the organisation that measured them, or “studies” with no method.

How each figure is checked

For every number in a Measured callout, chart or table, we record the source, the exact claim, the method and the date we accessed it. Where studies disagree, we report the disagreement and say which one we lean on and why. Where a finding is a correlation, we say so in the sentence.

Our own calculations, such as margins of error or cost models, are labelled as ours and show their formula. Practical advice from the desk is labelled as editorial, so you can weigh it differently from measured data.

What “Verified” means

Every edition carries a verification month, for example “Verified 2026-10”. It means the sources were checked and the vendor documentation re-read that month. Fast-moving topics, such as crawler names and platform reports, are re-checked monthly between scheduled reviews.

How books are updated

When a source changes, a platform renames a feature or a reader reports an error, we update the book. Every change is logged on the changelog with its date and what changed. Updates to the edition you bought are free.

Crediting policy

When we use someone’s public data, we name them in the sentence and credit them in the source list, with a link. We do not paraphrase a study without naming it. If you see your work used without credit, tell us and we will fix it in the next update.

Independence

No company named in a book pays for inclusion, reviews the text before publication or receives a commission from it. We do not use affiliate links.

Report an error

Email theb2bshelf@gmail.com with the book number, the page, what you think is wrong and the source you think is right. We check every report. Confirmed errors are corrected in the next update and logged with the date.