Sigma Score Methodology

How We Measure AI Visibility

The Sigma Score evaluates over 30 signals across three categories to determine how well AI search engines can discover, understand, and cite your business.

Scoring Overview

The Sigma Score ranges from 0 to 100 and is composed of three weighted categories. Each category evaluates a distinct dimension of your website's readiness for AI-powered search. The combined score reflects how well AI systems can find, parse, and cite your business.

25%

SEO

25% Weight

Traditional search engine optimization signals that ensure your site is technically sound, properly indexed, and accessible to all crawlers. These are the foundation of online visibility.

25%

Local SEO

25% Weight

Signals that determine how well your business appears in local search results, map packs, and location-based queries. Critical for businesses serving specific geographic areas.

50%

AEO

50% Weight

Answer Engine Optimization signals that determine whether AI systems like ChatGPT, Gemini, and Perplexity can discover, understand, and cite your business in AI-generated answers.

Why AEO Carries 50% of the Score

AEO directly determines whether AI systems can cite your content. SEO and Local SEO are foundational — without them, your site may not be crawled or indexed at all. But AEO is the differentiator in the AI search era. It is the layer that turns a well-optimized website into one that AI systems actively recommend.

We weight AEO at 50% because the signals it measures are the ones that separate sites AI engines cite from sites they ignore. A website can rank on the first page of Google and still be completely invisible to ChatGPT, Gemini, or Perplexity if it lacks the structured data, semantic markup, and AI crawler access that AEO signals evaluate.

Key Reasons

  • Structured Data Over Rankings

    AI search engines prioritize structured data over traditional ranking signals. A page with comprehensive JSON-LD is more useful to an AI than a page that ranks #1 without it.

  • Invisible Without AEO

    Without AEO, even high-ranking sites may be invisible to ChatGPT, Gemini, Perplexity, and other AI-powered answer engines that generate direct responses.

  • Binary Signals

    AEO signals are binary — you either have an llms.txt file or you do not. You either allow AI crawlers or you block them. There is no partial credit for signals that directly gate AI access.

SEO Signals (25% of Score)

These signals evaluate the foundational technical SEO elements that ensure your website can be crawled, indexed, and understood by search engines and AI systems alike.

Signal
What We Check
Title Tag
Presence and length of HTML title element
Meta Description
Presence and quality of meta description
H1 Heading
Single, descriptive H1 heading on the page
Open Graph Tags
og:title, og:description, og:image for social sharing
Canonical URL
Proper canonical tag to avoid duplicate content
Sitemap
Valid sitemap.xml accessible at root
Mobile Friendly
Responsive viewport meta tag
HTTPS
Secure connection via SSL certificate
Content Length
Sufficient content for indexability
Image Alt Text
Descriptive alt attributes on images

Local SEO Signals (25% of Score)

These signals evaluate your website's local search optimization — the structured data, contact information, and geographic signals that help search engines and AI systems connect your business to location-based queries.

Signal
What We Check
LocalBusiness Schema
JSON-LD LocalBusiness markup
NAP Consistency
Name, Address, Phone number present and consistent
Phone Number
Phone number visible on site
Physical Address
Business address displayed on site
Service Area Markup
Geographic service area defined in schema
Local Content
Content referencing local areas and neighborhoods
Google Business Profile Link
Link to or mention of GBP
Service Schema
Service type defined in structured data

AEO Signals (50% of Score)

Answer Engine Optimization signals are the most heavily weighted category because they directly determine whether AI-powered search engines can discover, parse, and cite your content. These are the signals that separate AI-visible businesses from AI-invisible ones.

Signal
What We Check
JSON-LD Structured Data
Any structured data via JSON-LD format
Schema Diversity
Multiple schema types (FAQPage, Service, Article, etc.)
FAQ Schema
FAQPage markup for common questions
llms.txt
File at /llms.txt for AI crawler guidance
AI Crawler Access
robots.txt allows GPTBot, Claude-Web, PerplexityBot
Content Answerability
Content structured in Q&A or direct-answer format
Semantic HTML
Use of main, article, section, nav semantic elements
Pre-rendering
Server-side rendered or statically generated pages
Entity Clarity
Clear, unambiguous business entity signals
Schema Completeness
Required fields present in schema markup

Our Scoring Philosophy

The Sigma Score is built on a set of principles that prioritize clarity, actionability, and real-world impact over arbitrary benchmarks.

Actionable, Not Punitive

The Sigma Score highlights what to fix, not what is wrong. Every failed check comes with a clear explanation and a specific action you can take to improve.

Every Signal Maps to an Action

We do not include vanity metrics. Every signal in the Sigma Score maps to a specific, implementable improvement that will increase your AI visibility.

Weighted by AI Impact

We weight signals by their impact on AI discoverability. A missing llms.txt file matters more than a slightly short meta description because it directly affects whether AI crawlers can parse your site.

A Starting Point, Not the Final Word

The Sigma Score is a diagnostic tool designed to give you a clear picture of where you stand. It is the beginning of the optimization process, not a definitive ranking of your business.

Continuously Updated

AI search is evolving rapidly. We update our methodology as new AI platforms emerge, new signals become relevant, and existing signals change in importance. The Sigma Score reflects the current state of AI search.

Methodology Changelog

We update our scoring methodology as AI search evolves. Here is a record of every change we have made to the Sigma Score.

v1.0January 2025

Initial methodology with 30+ signals across 3 categories

v1.1March 2025

Added llms.txt detection, expanded AI crawler checks

v1.2May 2025

Refined AEO weighting, added content answerability signals

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