Methodology

What Plumb measures, samples, infers, and refuses to guess.

You cannot see inside an AI model. You can see what it does to your site. Every number in Plumb says which of these it is, so an editor, a lawyer or a CFO knows how far to trust it.

MEASUREDSAMPLEDINFERRED

01Who it is for

Publishers where one article is worth real money

Plumb closes a loop: measure what AI takes, find the queries worth writing, draft the brief, measure again after it ships. That loop only pays for itself when a single well-placed article earns enough to matter.

Affiliate and commerce publishers
Finance, insurance, product reviews. A ranked article earns recurring commission every month it holds its position, so recovering one query that AI Overviews took can be worth thousands a year.
B2B and vertical trade publishers
SaaS, legal, healthcare, industry news. Subscriber lifetime value is in the hundreds of dollars, so one explainer that becomes the cited answer on an emerging question pays back fast.

General news and programmatic publishers get the measurement side, which is useful on its own for bot policy and licensing conversations, but the commissioning loop will not change their economics. Plumb is open about that rather than pitching to everyone.


02First-partyMEASURED

What is measured

Full coverage, from systems you own. Nothing here depends on asking a third-party model anything.

  • Every agent request, at your edge

    A Cloudflare Worker on your content routes reports each bot request to Plumb: the user agent, the path, the status, the time. The client IP is hashed at the edge and the raw address is never stored. Raw events are kept for 14 days; daily rollups are kept for good. Not on Cloudflare? Server logs can be uploaded instead.

  • Which agents are who they say they are

    A User-Agent string is a claim. Plumb checks each request against the IP ranges its vendor publishes (twelve feeds today, refreshed daily) and against RFC 9421 signatures where a vendor signs. A request from inside the ranges is verified. A known agent's name arriving from outside them is spoofed. A vendor that publishes nothing, which today includes Anthropic, leaves its agents unverifiable, and Plumb says so rather than guessing.

  • What your robots.txt said, and who listened

    Plumb fetches your live robots.txt daily and sets it against the edge log. For each agent it records the rule that applies, the requests to paths that rule disallows, and a verdict: honored, ignored, allowed, or no rule. Agents named in the file that never showed up are listed too.

  • Search Console

    Impressions, clicks and rank per query, with a flag for queries where an AI Overview rendered. This is how Plumb finds queries where impressions held while clicks fell, without scraping a results page.

  • Readers sent back

    Two sources. GA4 sessions whose referrer is an AI assistant (chatgpt.com, claude.ai, perplexity.ai and the rest of a maintained list), and referrals the Worker sees directly at the edge. Plumb reports crawls per referral for each platform from the same log, so the two sides of the ratio come from the same place.


03ProbesSAMPLED

What is sampled

Plumb asks the assistants questions on a schedule and records what comes back. It is the only way to see citations from the outside, and it is noisy.

  • The weekly citation panel

    500 questions across the topics that matter to affiliate and trade publishers, put to ChatGPT, Claude, Gemini and Perplexity every Monday. Plumb records which domains each answer cites and in what order. This is where share of voice and emerging demand come from.

  • Why it is noisy

    The same question, on the same model, at temperature zero, in the same week, returns different citations hour to hour. Moves under 15 points week over week are inside the noise. Plumb shows trend lines, not single readings, and never uses the panel for an absolute claim about your visibility.


04ModelsINFERRED

What is inferred

Estimates, scores and text that a model produced from the measured and sampled data. Useful for ordering decisions. Never a fact on its own.

  • Priority and recoverable value

    The priority score on a bleeding query weighs impressions, the size of the click drop and how close you sit to the top. The dollar figure applies your own conversion economics to that. Both are orderings for a planning meeting, not facts, and carry the inferred label wherever they appear.

  • What Plumb's models write

    Page recaps, the briefing paragraph on the overview, commission briefs, proposed edge rules and answers from Ask Plumb are written by a model that can only call Plumb's own tools. Every line names the tool it called, and the numbers keep the label they had in the tool result. A recap can be wrong about emphasis; it cannot invent a number that is not in the data.

  • Readiness scores and story diagnostics

    The article readiness score weighs structure, freshness, metadata and similar factors against published citation research. The label on an ignored story (schema, timing, paywall, stale, duplicate) comes from a small decision tree. Treat both as hypotheses to check, not conclusions.

  • The hidden AI share of direct traffic

    A Bayesian estimate of how many direct sessions began in an AI conversation, from the conversion lift of direct over organic. The output is a range. The sweep chart shows how far it moves when the prior moves, because it should.


05Unknowable

What Plumb will not claim to know

  • What a model thinks of your content

    Retrieval scores, weights, and why an answer cited a competitor instead of you are private to the model's operator. No outside tool can see them. Plumb can correlate crawl concentration with citation outcomes; it cannot explain the choice.

  • What real users are asking

    The questions typed into ChatGPT or Perplexity are not shared with publishers. Plumb samples a panel of questions it writes. A product that shows you real user queries is either sampling too or making them up.

  • Whether a page ended up in training data

    A crawl log shows a bot fetched a page. It says nothing about what happened next. Statements about training-set inclusion are speculation, and Plumb does not make them.


06The panelPANEL

How publishers are compared

When several publishers run Plumb, it can show a first-party median instead of citing someone else's research PDF.

  • Three publishers minimum

    No cross-publisher figure is shown below three participating tenants. Under that, the dashboard shows the published research figure and names its source.

  • Quantiles only

    The panel returns a median with the 25th and 75th percentiles. No minimum, no maximum, no per-tenant rows. Your own tenant contributes but cannot be picked out.

  • Computed live

    Aggregates are computed on request with a five-minute cache. There is no archive. Leave the panel and your data leaves it at the next refresh.


07Independence

Why not the marketplace's dashboard

Two kinds of vendor already show publishers numbers about AI traffic. Both have a stake in what the numbers say.

Licensing marketplaces
TollBit, ScalePost, ProRata and others sit in the payment flow and keep a share of what they broker. Their dashboard reports their own numbers.
Edge and bot-management vendors
Cloudflare, DataDome, HUMAN, Akamai. They enforce at the edge and report their enforcement outcomes.
Plumb
The publisher's own record, from the publisher's own logs, with no take rate and no stake in the outcome. It is what checks the other two. The reconciliation page exists for exactly that.

08Not in scope

What Plumb does not do

Brand sentiment
How assistants feel about a brand is a different product with a different buyer, and it needs a panel of real user conversations that Plumb does not have. Plumb will not build a sampled substitute and present it as if it were that.
Writing the articles
Plumb drafts the brief: what to write, why this call over the alternative, which structural elements earn citations. It does not write the piece. Generated articles at scale are the content that assistants are already displacing.
Programmatic display yield
Plumb does not tune CPMs or ad stacks. Where an article earns a fraction of a cent in display, the commissioning loop cannot pay for itself. Plumb is built for publishers where one article is worth real money: affiliate, commerce and trade.
methodology v2.0 · 2026-09-11 · sources: Cloudflare Worker edge log, vendor IP-range feeds, RFC 9421 signatures, robots.txt, Google Search Console, GA4, weekly citation panel, content catalog, Plumb panel (N of 3 or more)