Methodology / Limitations

Limitations & caveats

Every measurement method has boundaries. The Magpire Index is a directional signal, not a definitive judgment. We document its known limitations below so firms, researchers, and partners can interpret the results responsibly.

Known limitations

Snapshot, not continuous monitoring

The Magpire Index reflects the firm's AI visibility at the time the audit was run. AI engine responses change as models are updated, training data shifts, and new sources are indexed. A score is a point-in-time measurement, not a permanent rating.

Four engines, not the full AI landscape

We test ChatGPT, Claude, Gemini, and Perplexity. Other AI systems (Microsoft Copilot, Grok, DeepSeek, specialised legal/medical AIs) are not included. A firm invisible to all four tested engines may still be cited by other AIs — though we consider that unlikely for accounting-firm buyer queries.

Prompt sensitivity

Different phrasings of the same buyer intent can produce different AI responses. Our prompt set is designed to cover the most common query patterns, but we cannot exhaust every possible formulation. Small wording changes may shift which firms an engine cites.

AI engines are black boxes

We observe outputs, not internal ranking logic. When an AI declines to cite a firm, we cannot determine whether the cause is absence from training data, a recency filter, a safety alignment decision, or a genuine lack of relevance. The Index reports what the engines do, not why.

Geographic and specialism coverage

Aggregated public statistics suppress any cell containing fewer than five firms. This means city-level or specialism-level breakdowns are not available for smaller markets until the dataset grows. An empty stat does not imply a score of zero — it means the data is insufficient to report.

No legal, financial, or professional advice

The Magpire Index is a visibility measurement tool. It does not constitute financial, legal, or professional advice. Firms should consult their own advisors before making business decisions based on their Index score.

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Sam Hoye, founder of Magpire
Sam Hoye ACMA CGMA
ACMA · CGMA · Founder, Social Commerce Accountants · 50+ accounting firm clients · Updated March 2026