The Magpire Index Explained

If a prospective client types "best accountant for contractors in Leeds" into ChatGPT, does your firm appear in the answer? The Magpire Index tells you exactly how likely that is — and what is holding you back if the answer is no.

This guide walks through every component of the score: what it measures, how it is weighted, how it differs by firm type, and what you can realistically do to move it. No prior knowledge of AI Engine Optimisation (AEO) is assumed.

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What Does the Magpire Index Actually Measure?

The Magpire Index is a composite visibility score that measures how prominently an accounting firm appears as a cited or recommended source inside AI-generated answers across five major engines: ChatGPT (OpenAI), Claude (Anthropic), Perplexity AI, Gemini (Google DeepMind), and Google AI Overviews.

It does not measure whether your website ranks on page one of a traditional search results page. It measures something more specific: whether the large language models and retrieval-augmented systems that power these engines treat your firm as an authoritative, trustworthy, and citable source when a user asks a question that your firm could answer.

Each engine retrieves, synthesises, and presents information differently. ChatGPT's browsing and GPT-4o retrieval layer surfaces sources it deems structured and credible. Perplexity cites sources inline and weights pages that give direct, factual answers. Google AI Overviews draw heavily on entities and schema signals that Google's Knowledge Graph already recognises. Claude leans on content depth and author credibility. The Magpire Index aggregates your performance across all five, weighted by their relative query volume in the UK and US accounting search market as of Q2 2026.

The output is a single number between 0 and 100. A score of 0 means the engines do not recognise your firm as a source worth surfacing. A score of 100 means your firm is the reference-class answer for the queries it targets. Most accountancy practices that have never run an AEO programme sit between 12 and 28 on their first audit, as a typical benchmark.

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Why Traditional SEO Scores Miss This Entirely

Standard SEO metrics — Domain Authority, organic keyword rankings, Core Web Vitals, backlink counts — were designed to predict one thing: where a page lands on a Google Search results page. They are useful for that purpose. They are poor predictors of AI engine visibility, for a structural reason.

Google's organic ranking algorithm rewards signals of relevance and authority that it can measure at the page and domain level: inbound links, keyword density, click-through rate, dwell time, mobile performance. These signals help a crawling, indexing, ranking system decide which page to return in a list.

AI engines do something different. They do not return a list. They synthesise an answer and, in doing so, decide which sources deserve to be the factual backbone of that answer. The signals they weight are:

Structured answers. A page that opens with a direct, well-formed answer to a specific question is far more likely to be lifted than a page that buries the answer in paragraph five. Perplexity's retrieval pipeline, for instance, heavily favours content that resembles a trustworthy, encyclopaedia-style entry — a clear claim followed by supporting evidence.

Author credentials. Claude and ChatGPT both show sensitivity to whether content is attributable to a named, verifiable professional. An article signed by a qualified accountant with ICAEW or ACCA membership, a traceable LinkedIn profile, and a consistent publishing history is treated differently from anonymous web copy. This is analogous to Google's E-E-A-T signals, but applied earlier in the generation process rather than as a post-ranking filter.

Schema markup. Google AI Overviews draw heavily on structured data. A firm whose website uses LocalBusiness, AccountingService, FAQPage, and Person schema correctly is giving Gemini and Google AI Overviews parseable, trustworthy entity data. Most accountancy websites have none of this.

Sector authority. AI engines infer topical depth from the breadth and consistency of a firm's published content on a defined set of subjects. A firm that has published 40 coherent, interlinked articles about R&D tax credits is treated as an authority on R&D tax credits. A generalist firm with thin, scattered content on dozens of topics is treated as an authority on none of them.

A firm can have a Domain Authority of 45, rank on page one for "accountant London", and still score 14 on the Magpire Index. These are measuring different things.

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The Five Weighted Categories

The Magpire Index is built from five categories, each with its own sub-signals and weighting. The weights are not fixed — they shift depending on firm type, which is covered in the next section. What follows is the baseline description of each category.

1. AI Presence (Default weight: 30%)

AI Presence is the most direct measure in the index. It captures whether your firm is actually being mentioned, cited, or recommended by the five target engines when users ask relevant queries.

This is assessed by running a structured battery of probe queries — questions that a prospective client of your firm type would realistically ask an AI assistant — and recording whether your firm appears, whether it is named as a recommendation, and whether it is cited as a source. Each engine is probed separately. The results are normalised and aggregated.

AI Presence rewards firms that already have some footprint in the engines' training data or retrieval indexes. It is the category most immediately affected by content publishing and schema work, because those are the signals retrieval-augmented engines act on fastest.

2. Content Quality (Default weight: 25%)

Content Quality scores the degree to which your published content is structured in a way that AI engines can extract, trust, and cite.

Sub-signals include: the proportion of content that opens with a direct answer sentence; the use of question-led headings (which match how users phrase queries to ChatGPT and Perplexity); factual specificity (named figures, dates, HMRC or IRS references, ICAEW guidance citations); internal linking coherence; and reading-grade appropriateness for a professional audience.

Content Quality does not reward volume for its own sake. Fifty thin blog posts with no structured answers score lower than ten deep, well-structured guides. The category is designed to reward the kind of writing that a senior qualified accountant would produce for a sophisticated client — precise, direct, and evidenced.

3. Technical (Default weight: 20%)

Technical scores your website's underlying infrastructure as it affects AI engine crawlability and entity recognition.

The primary sub-signals are schema markup coverage (LocalBusiness, AccountingService, FAQPage, BreadcrumbList, Person, Article), page load performance on mobile (because Gemini's retrieval layer inherits Google's mobile-first indexing), HTTPS and security hygiene, crawl accessibility (whether key pages are reachable by AI crawlers, some of which use different user-agent strings from Googlebot), and canonical tag discipline.

Most accounting firm websites score poorly here not because of complex technical failures but because schema implementation was never prioritised. Adding correct FAQPage schema to a well-written Q&A page can move the Technical sub-score meaningfully within days of re-indexation.

4. Visibility Signals (Default weight: 15%)

Visibility Signals captures the broader digital footprint that tells AI engines your firm is a real, established, trustworthy entity — not a thin-content site.

Sub-signals include: Google Business Profile completeness and review volume; consistent NAP (Name, Address, Phone) data across directories and citation sites; presence and activity on LinkedIn (which both ChatGPT's browsing layer and Perplexity's retrieval system access); mentions in professional press (Accountancy Age, AccountingWEB, Going Concern in the US); and registration data from Companies House (UK) or State licensing boards (US) that is consistent with what the website claims.

Visibility Signals is the category most familiar to traditional SEO practitioners, but it is applied here in a different context: not as a ranking factor for a results page, but as entity-verification data that AI engines use to decide whether to trust a source.

5. Authority (Default weight: 10%)

Authority scores the depth and coherence of your firm's topical expertise as expressed through its content and credentials.

Sub-signals include: the presence of named authors with verifiable professional qualifications (ACCA, ICAEW, CPA, CMA — ACMA CGMA is recognised); the consistency of those authors' publishing history; the number of defined topic clusters the firm has built genuine content depth in; inbound links from recognised professional bodies or regulatory pages; and any formal accreditations (HMRC-recognised tax agent status, FCA authorisation if relevant, PCAOB registration for US audit firms).

Authority has the lowest default weight because it is the hardest to move quickly and the most dependent on genuine practice history. It also has a compounding effect: a high Authority score amplifies the AI Presence score, because engines are more willing to cite sources they can verify are qualified.

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How Firm Type Changes the Weighting

The five categories are not weighted equally for every firm. The Magpire Index uses three firm-type profiles — Local, Niche, and Hybrid — because the queries these firms need to win are structurally different.

Local firms serve clients in a defined geography. Their prospective clients ask location-qualified queries: "accountant for small business in Manchester", "VAT registration help near me". For these firms, Visibility Signals carries more weight (raised to 25%) because local entity signals — Google Business Profile, NAP consistency, local citations — are exactly what AI engines use to return geographically relevant answers. AI Presence weight falls slightly to 28%, and Authority falls to 7%.

Niche firms serve clients defined by sector, structure, or tax situation — contractors, property investors, creative industries, crypto traders. Their prospective clients ask expertise-qualified queries: "accountant who understands IR35", "R&D tax credit specialist for SaaS companies". For these firms, Content Quality is raised to 32% and Authority to 15%, because the engine's decision to cite a niche firm rests almost entirely on demonstrated topical depth. Visibility Signals falls to 10% because geography is irrelevant to the query.

Hybrid firms have both a defined geography and one or more defined niches — a Manchester-based firm specialising in construction subcontractors, for example. Weights are balanced across all five categories, with a slight uplift to Content Quality (28%) and Visibility Signals (20%).

Worked Example: Same Raw Signals, Different Scores

Suppose two firms each have the following raw signals: one detailed FAQ page on IR35, correct LocalBusiness schema, a Google Business Profile with 34 reviews, three articles on contractor taxation, and one named ACCA-qualified author.

Firm A is a local generalist in Bristol. Its Magpire Index scores as follows under local weighting: AI Presence 16/30 (not yet appearing in local AI queries), Content Quality 18/25 (good FAQ, thin article depth), Technical 14/20 (schema present), Visibility Signals 17/25 (strong GBP), Authority 5/10 (one qualified author). Total: 70/110 normalised to ~64.

Wait — that is the same raw signals. Here is Firm B.

Firm B is a niche firm positioning exclusively as a contractor accountant. Under niche weighting: AI Presence 16/30, Content Quality 18/32 (same three articles but now scored against a 32-point ceiling — they represent shallow coverage for a specialist), Technical 14/20, Visibility Signals 10/10 (capped at 10 in niche weighting, so full marks), Authority 8/15 (one ACCA author is more meaningful for a specialist). Total: 66/107 normalised to ~62.

The scores are close here, but the gap widens dramatically with investment. If Firm B publishes eight more deep contractor articles, its Content Quality moves to 28/32 and its Authority to 12/15, pushing its index to ~82. The same eight articles published by Firm A (the local generalist) would move its index only to ~71, because the weighting structure does not reward deep niche content as heavily for a generalist positioning.

The practical implication: a niche firm that commits to content depth gets disproportionate index movement per hour of effort invested.

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What Does a "Good" Score Look Like?

There is no universal threshold, because the index is comparative as well as absolute. The benchmarks below are illustrative, based on the distribution of firms audited through the Magpire platform.

Local firms: A score above 55 indicates a firm that is beginning to appear in AI-generated answers for location-qualified queries. Above 70, it is appearing consistently and being cited. Above 85 is category-leading visibility for a local market.

Niche firms: The bar is higher because AI engines hold specialists to a higher evidentiary standard. A score above 60 indicates appearing in some specialist queries. Above 75, appearing in most relevant queries. Above 88 is a defensible market position — the firm is the reference-class answer for its specialism in the markets it targets.

Hybrid firms: Scores behave more like local firms at lower ranges and more like niche firms at the top end. Above 72 is a strong hybrid position.

What Moves the Score Fastest?

The fastest-moving levers, in approximate order of speed-to-impact:

Schema implementation moves the Technical sub-score within one to two weeks of re-crawl. Adding FAQPage, AccountingService, and Person schema to existing pages requires no new content and can be done by a developer in a day.

Publishing direct-answer content — pages and articles that open with a clear, factual answer to a specific question — moves AI Presence and Content Quality within four to eight weeks as retrieval indexes update. Perplexity re-crawls fast; ChatGPT's browsing layer is slower.

Google Business Profile optimisation moves Visibility Signals quickly for local and hybrid firms. Complete categories, service descriptions that match your positioning, and a consistent stream of responses to reviews all help.

Author credentialing — adding verifiable author profiles with qualification details, linking to LinkedIn, and ensuring ICAEW or ACCA registration is findable — moves the Authority sub-score and has a halo effect on Content Quality scoring.

Topic cluster development (the sustained build-out of interlinked, deep content on a defined subject) is the slowest lever but produces the largest long-term index gain, particularly for niche firms.

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What the Magpire Index Does Not Measure

Being specific about limitations is part of using any score honestly.

Transactional performance. The index measures visibility and credibility signals, not whether a prospective client who finds your firm in an AI answer actually contacts you, signs an engagement letter, or stays as a client. A firm can score 85 on the index and have poor conversion if its website UX is weak or its pricing is uncompetitive. The index is a top-of-funnel signal.

Fee quality and profitability. A firm that wins high-visibility queries for low-value work is not necessarily better off. The index does not distinguish between a query worth £200/year in recurring fees and one worth £20,000/year. Targeting strategy — which queries to pursue — sits outside the index itself.

Referral and relationship pipeline. Many established accountancy practices derive the majority of their new business from professional referrals — solicitors, IFAs, mortgage brokers, insolvency practitioners. The Magpire Index does not capture the health of that network. A firm with a score of 30 and a strong referral ecosystem may be commercially healthier than a firm scoring 75 that depends entirely on inbound digital enquiries.

Content accuracy and professional compliance. The index rewards structured, credible, well-attributed content. It does not audit whether the underlying tax or accounting advice is correct. Firms remain responsible for the professional accuracy of everything they publish under their name. ICAEW's practice standards and ACCA's Code of Ethics apply regardless of what the index says.

Competitive moat. The index is a snapshot. A competitor firm that launches an intensive AEO programme today can close a large gap within two to three quarters, particularly at lower absolute score levels. The index should be treated as a live metric requiring ongoing attention, not a permanent status.

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How to Read Your Own Score

When you run a Magpire audit, your report breaks down all five category scores individually, shows you which engine-specific probe queries your firm appeared in and which it missed, and flags the highest-impact actions specific to your firm type and current position.

The index is designed to be re-run quarterly — the same discipline you would apply to reviewing management accounts — because AI engine behaviour changes as models update, retrieval pipelines shift, and competitors act.

The free audit takes under five minutes to set up and returns your baseline Magpire Index within 24 hours, along with the three highest-leverage actions for your firm type. That is the right starting point if you have read this far and are not yet sure where your firm stands.