Index S: Generative Structure

(40% Weight) The Blueprint for AI. Measuring semantic cleanliness for flawless AI parsing.

I. The Blueprint for AI

The Structure Index (S) is the component of the AI Interpretation and Accessibility Score (AI-IA Score) that measures how well a website's code and content hierarchy are organized for efficient parsing and understanding by an AI. It is weighted at 40% of the final AI-IA Score.

The formula for the Structure Index (S) is based on measuring Semantic Cleanliness and Heading Hierarchy, returning a score from 0 to 100.

II. 📐 The Structure Index (S) Formula

The score is calculated as a simple average of the two core structural scores: Semantic Score and Coherence Score.

S = (Semantic Score + Coherence Score) / 2

III. Sub-score Definitions

1. Semantic Score (The Tag Quality)

This measures the quality of the HTML tags, ensuring the AI can easily isolate the most important content. It's the ratio of semantic tags (e.g. `<main>`, `<article>`) versus generic `<div>` containers.

2. Coherence Score (The Outline Quality)

Evaluates how well the heading structure follows a logical outline. It checks for a single `<h1>` and penalizes for skipping heading levels (e.g., jumping from an `<h2>` to an `<h4>`).