Introduction to Share of AI Voice (SOAV)
In traditional search engine optimisation, we have long relied on Share of Voice (SOV) based on keyword rankings and estimated click-through rates. However, as generative search engines like Google Gemini, Search Generative Experience (SGE/AI Overviews), and Perplexity gain traction, the metric must evolve. Share of AI Voice (SOAV) measures the frequency and prominence with which a brand (or a competitor) is cited across a statistically significant set of industry-relevant prompts.
Unlike traditional search, where a rank of #1 is the primary goal, AI visibility is binary: you are either cited as a source or you are not. SOAV allows practitioners to quantify their digital footprint within the 'latent space' of Large Language Models (LLMs) and provide clients with a concrete benchmark of their authority relative to their peers.
The Core Methodology
To calculate SOAV accurately, you cannot rely on a single query. You must define a 'Prompt Set'—a collection of 50 to 200 queries that reflect your target audience’s journey. This methodology comprises four distinct stages: Selection, Extraction, Normalisation, and Calculation.
1. Defining the Prompt Set
Your prompt set should not just be keywords; it should reflect the natural language patterns found in conversational search. Categorise these into:
- Informational (Top of Funnel): "What are the best sustainable fabrics for sportswear?"
- Commercial (Middle of Funnel): "Compare recycled polyester vs organic cotton durability."
- Transactional (Bottom of Funnel): "Where can I buy ethically made gym leggings in the UK?"
- Brand-Specific: "Is [Brand Name] a sustainable company?"
2. Data Extraction and Citation Mapping
You must run these prompts through target AI engines. For each response, identify the cited domains. In an AI Overview or a Perplexity response, citations are typically indicated by superscript numbers or source cards at the bottom. Record every domain mentioned. If a domain is mentioned three times in one response, it still counts as 'present' for that specific prompt in a binary model, though some advanced practitioners weight by frequency.
3. Normalisation
Clean the data by grouping subdomains (e.g., blog.brand.com and www.brand.com) and identifying 'Inertia Sources'—third-party sites like Wikipedia or Reddit that consistently appear but are not direct competitors. This ensures the SOAV reflects the competitive commercial landscape rather than just general web authority.
Worked Example: High-End Coffee Machines
Imagine we are representing 'BeanMaster', a boutique espresso machine manufacturer. We want to measure our SOAV against 'JavaPro' and 'GrindCo'.
The Setup:
- Prompt Set: 100 queries covering 'Home espresso maintenance', 'Best prosumer machines 2024', and 'How to dial in espresso'.
- Engine: Google AI Overviews.
The Findings:
- Total Prompts: 100
- BeanMaster cited in: 15 prompts
- JavaPro cited in: 30 prompts
- GrindCo cited in: 10 prompts
- Affiliate Review Sites (e.g., Wirecutter): 45 prompts
The Calculation:
To find the SOAV, use the formula: (Brand Mentions / Total Prompts) * 100.
- BeanMaster SOAV: 15%
- JavaPro SOAV: 30%
- GrindCo SOAV: 10%
Analysis: While BeanMaster might have better traditional SEO rankings for 'espresso machines', JavaPro is dominating the AI citations. This suggests JavaPro has better 'LLM-optimised' content—likely structured data, clear entity relationships, and inclusion in the specific review clusters the AI is pulling from. BeanMaster needs to investigate which specific pages JavaPro is winning with and reverse-engineer their citation triggers.
Advanced Metric: Citation Intensity
Beyond basic presence, we can measure 'Citation Intensity'. If a prompt generates a response with five citations and your brand is three of them, your intensity is higher than a brand with one citation. This is a leading indicator of 'Topic Authority'. To calculate this, divide the total number of citations your brand received by the total possible citations across all prompts in the set.
Tools for Tracking
While manual tracking is possible for small sets, scale requires automation. Current practitioners use:
- Custom Python Scripts: Using Playwright or Selenium to scrape AI responses (check terms of service before proceeding).
- Specialised AI Tracking Tools: Platforms like Authoritas or ZipTie which are building specific modules for SGE and Gemini tracking.
- LLM APIs: Querying GPT-4o or Claude via API to see if they cite your brand when asked specifically about your niche (note: this measures training data presence, not real-time search retrieval).
Strategic Deployment of SOAV Data
SOAV is a powerful reporting tool for clients. It moves the conversation away from 'Where am I on page 1?' to 'Am I part of the AI-generated answer?'. If your SOAV is lower than your traditional market share, it indicates a 'Visibility Gap'. This gap is often caused by technical barriers (e.g., blocking bots in robots.txt) or content barriers (e.g., lack of clear, factual, and citable statements).
Putting it into Practice
To implement SOAV tracking for your next client report, follow these steps:
- Select 50 High-Value Queries: Focus on the 'Problem/Solution' phase of the buyer journey.
- Create a Spreadsheet: Columns for 'Prompt', 'Brand Present (Y/N)', 'Competitor A Present (Y/N)', and 'Top Cited Domain'.
- Run the Prompts: Using a clean browser profile or an incognito window, trigger the AI response for each prompt.
- Calculate the Percentage: Divide the 'Yes' count by 50 for each brand.
- Identify the 'Gap': Look for prompts where competitors are cited but you are not. Analyse the 'Source' URL the AI used for the competitor. Is it a product page, a blog post, or a third-party review?
- Optimise: Update your corresponding content to match the structure and depth of the winning sources.
By consistently measuring SOAV over a quarter, you can demonstrate the direct impact of your AI Visibility (AEO) efforts, showing a clear upward trend in citation frequency even if traditional rankings remain static.