The method in full
How the Southlume Index measures AI visibility
The Southlume Index measures who AI assistants recommend across Australian categories – which businesses get named when real buyers ask real buying questions, and how consistently. This page is the method in full.
One rule governs everything we publish: every number carries a date, a question-set version, and a market. If a figure can’t tell you when it was measured and how, we don’t publish it.
Ask once and you get a point. Ask twenty times and a range forms – the grey band. We publish the middle, and we print the band beside it so you can see how much to trust it.
The method, in one table
| Questions | Fixed buyer questions, plain and non-branded, per category – “best mortgage broker in Sydney”, asked the way a customer would |
| Question set | Versioned like software – currently v1, 5 July 2026. If a question changes, the version changes; nothing is reworded quietly |
| Assistants | ChatGPT · Perplexity · Gemini · Claude (as at v1) |
| Market | Australia at launch – the method reads any market the assistants answer |
| Measures | Mention rate – how often a business is named. Citation rate – how often its site is linked as a source. Never blended into one score |
| Sampling | Two stages – a screening pass across a category, then a deeper pass where precision matters most. Sample sizes publish with each edition |
question set v1 · 5 Jul 2026 · market Australia
A business can be named often and cited never – we’ve measured the gap, which is why they stay separate.
How we tell a real change from noise
Ask an AI the same question four times and the recommendations can change substantially – we’ve measured that too. Any single reading is partly the model’s own randomness, so every figure we publish carries its stability band: the range randomness alone would produce. A change only counts as movement when it clears the band. A mention rate that rises inside its band is wobble, not a win – and we say so.
More repeat runs narrow the band; that’s what the two-stage sampling buys. On our charts, orange means one thing only: moved beyond its stability band.
What counts as a business
An entity is a business, not a string of text. Assistants emphasise headings and half-sentences alongside the names they recommend, and write one business several ways in the same answer – so counting text overstates how many were named and understates how often one was held.
| Counted | A named business or practitioner – the thing a customer could book |
| Not counted | Prose, headings, addresses, opening hours, dates, bare place names. Each exclusion publishes with its reason |
| Variant spellings | Merged – but only where the names share a distinctive word, so two clinics sharing a generic or geographic term stay separate |
| Identity | A business website domain where the assistant links one (~3% here), the name everywhere else – name-matched counts carry that caveat |
entity extraction v2 · 22 Jul 2026
Extraction is versioned like the question set – this is v2, 22 July 2026 – and counts published under v1 are carried beside the current ones in every dataset, not replaced.
Dated, versioned, and published in full
Every reading is stamped – date, question-set version, extraction version, market – and editions are numbered, so any figure can be cited precisely.
| what publishes | the commitment |
|---|---|
| Movements that clear the band | Reported as real, with the band drawn on the bar |
| Movements inside the band | Reported as wobble – named as such |
| Quarters where nothing moved | Reported as exactly that. A boring result is still a result |
| Our own visibility | Logged from a baseline of zero – the method applies to us first |
What the numbers do not say
Zero means: not found on these questions, on this date, in this market – never “invisible everywhere, always”. The questions are a sample – a disciplined one, but a sample.
Prompt checks are a sample; referral analytics are the ground truth of actual AI-driven visibility. A zero here is ‘not found on these prompts’, never ‘invisible’.
Frequently asked questions
How does Southlume measure AI visibility?
What is a stability band?
How often does the Index publish?
Which AI assistants does Southlume check?
What’s the difference between mention rate and citation rate?
Can a score be zero?
The method, in use
Edition 1 is in measurement now.
notify me · edition 1Question set v1, 5 Jul 2026 · market Australia.