How Do Google and LLMs Decide Who Is an Expert? Do I Need Topical Authority for Both?
How do Google and LLMs decide who is an expert? This is one of the most important questions in SEO right now. The answer determines whether your brand gets cited by AI or ignored.
“I have good content, good backlinks, and years of experience. But when I ask ChatGPT about my industry, my brand is nowhere to be found. Why?”
The frustration is real. You can rank on Google and still be invisible to AI search engines. Why? Because Google and LLMs (Large Language Models) judge expertise differently.
According to Gartner, traditional search volume will drop 25% by 2026. Understanding how both Google and AI platforms evaluate authority is essential for staying visible.
This guide is brought to you by HumanReach.ai, an organic growth agency that helps brands become trusted sources in the AI search landscape. The framework below is the same methodology HumanReach.ai uses to build topical authority across both Google and LLMs.
If you are new to this space, read our guides on Generative Engine Optimization vs SEO and whether you need to adapt to AI search in 2026 first.
📑 Table of Contents
- How Google decides who is an expert
- How LLMs decide who is an expert
- The key differences between Google and LLMs
- What is topical authority and why it matters for both
- 90-day roadmap to build authority for both
- Frequently Asked Questions (FAQ)
- The bottom line
How Google decides who is an expert
Google’s version of expertise relies on signals of trust and popularity. Here are the main factors:
- Domain Authority (DR): How many quality backlinks point to your site? More links from trusted domains = higher authority.
- PageRank: Google’s original algorithm that measures link equity passing through the web.
- Age of domain: Older domains tend to have more trust (though newer sites can still win).
- E-E-A-T signals: Experience, Expertise, Authoritativeness, and Trustworthiness — measured through author bios, citations, and external references.
- Content depth: Does your content cover a topic completely? Thin content rarely ranks for competitive terms.
- User engagement: Click-through rates, time on page, bounce rates — all influence Google’s perception of quality.
Bottom line for Google: Expertise is measured through what others say about you (backlinks) and how users interact with your content (engagement).
For a complete framework on getting cited by AI, read how to get your brand into AI answers.
How LLMs decide who is an expert
LLMs (ChatGPT, Perplexity, Gemini) judge expertise very differently from Google. Here is what matters for AI-powered discovery:
- Helpful answers, not links: LLMs prioritize content that directly answers a question. They don’t care about backlinks.
- FAQ schema: Pages with structured Q&A are 2-3x more likely to be cited. This is the single highest-ROI action for AI citations.
- Reddit and Quora presence: 47% of Perplexity citations come from Reddit. If you ignore forums, you ignore almost half the opportunities.
- Fresh content: LLMs prefer content published or updated in the last 30-90 days.
- Conversational language: Content written as if answering a human question (not keyword-stuffed) is easier for LLMs to extract.
- Q&A format (H2 = question, paragraph = answer): This matches exactly how LLMs are trained to extract information.
Bottom line for LLMs: Expertise is measured through clarity, structure, and usefulness — not popularity or backlinks.
For a deeper dive on tracking, read our guide on how to measure AI search performance.
The key differences between Google and LLMs
| Factor | LLMs (ChatGPT, Perplexity, Gemini) | |
|---|---|---|
| Primary signal | Backlinks (what others say) | Helpful answers (clarity) |
| Content preference | Depth + keywords | Q&A format + schema |
| Trust signals | Domain age + EEAT | FAQ schema + freshness |
| Platform importance | Your website | Reddit, Quora, LinkedIn |
| Time to results | 6-12 months | 3-6 weeks |
What is topical authority and why it matters for both
Topical authority means covering a subject completely — not just one article, but many articles that answer every related question a user might have.
Why Google loves it: Google sees topical authority as a sign that your site is the go-to resource for a subject. It helps you rank for multiple related keywords, not just one.
Why LLMs love it: When you cover every angle of a topic, you answer more questions that users might ask. LLMs are more likely to cite a source that has comprehensive, structured answers.
The good news: Building topical authority for Google also helps you win AI citations. You don’t need two separate strategies. You need one strategy that serves both.
90-day roadmap to build authority for both
Days 1-30: Foundation (for both)
- Choose 1 core topic (e.g., “fractional sales hiring”)
- Audit your existing content
- Identify 20 questions users ask about this topic (use Reddit, Quora, AnswerThePublic)
- Create FAQ schema for each question
Days 31-60: Depth (for Google)
- Write a pillar page (3000+ words) covering the core topic
- Create 5-10 cluster articles answering specific sub-questions
- Internal link everything (pillar → clusters, clusters → pillar)
- Build backlinks to the pillar page
Days 31-60: Clarity (for LLMs)
(Run this in parallel with the depth phase)
- Rewrite pages in Q&A format (H2 = question, paragraph = answer)
- Answer 50 questions on Reddit and Quora in your niche
- Add schema to every page
- Use conversational language (write like you speak)
Days 61-90: Authority (for both)
- Monitor citations in AI platforms weekly
- Track branded search lift (Google Search Console)
- Update old content (freshness matters for both)
- Repeat for the next topic
One topic at a time. Don’t try to cover everything. Depth > Width for both Google and LLMs.
✨ Still wondering if building topical authority is worth the effort? You don’t have to figure it out alone.
At HumanReach.ai, we build content engines that turn your expertise into trusted citations across both Google and AI platforms. Visit HumanReach.ai to explore how we help brands win in the AI-powered discovery era.
Frequently Asked Questions (FAQ)
1. How do Google and LLMs decide who is an expert?
How do Google and LLMs decide who is an expert? Google relies on backlinks, domain authority, and user engagement signals. LLMs prioritize helpful answers, structured data (FAQ schema), forum presence (Reddit), and conversational language. You need different tactics for each, but they can be built together.
2. Do I need topical authority for both Google and LLMs?
Yes. Topical authority helps you rank on Google for multiple keywords and increases your chances of being cited by LLMs. When you cover a topic completely, you answer more questions that users might ask. One strategy can serve both platforms.
3. How long does it take to build topical authority?
For Google: 6-12 months to see significant ranking improvements. For LLMs: 3-6 weeks to see first citations. The 90-day roadmap above accelerates both by focusing on depth, structure, and schema.
4. What is the #1 fastest way to get cited by LLMs?
FAQ schema. Pages with FAQ schema are 2-3x more likely to be cited by ChatGPT and Perplexity. It takes 2 hours to implement on your top 10 pages. It’s the highest-ROI action for AI citations.
5. Do backlinks still matter for AI citations?
Not directly. LLMs don’t crawl backlinks the way Google does. However, backlinks help your content get discovered and indexed faster, which indirectly helps AI platforms find your content.
6. Can a small brand beat a big brand in topical authority?
Yes. Google and LLMs prioritize depth over domain size. If you cover a niche topic more completely than a big brand, you can outrank them. Focus on one topic at a time and go deep.
7. What is the single biggest mistake brands make with topical authority?
Trying to cover too many topics at once. Pick one core topic. Build depth. Then move to the next. Depth always beats width for both Google and LLMs.
The bottom line
How do Google and LLMs decide who is an expert? Google looks at backlinks and authority signals. LLMs look at clarity, structure, and helpfulness.
Do I need topical authority for both? Yes. But the good news is that building for one helps the other. One strategy. Two outcomes.
Your 90-day start today:
- Pick one core topic
- Add FAQ schema to your top 10 pages
- Rewrite 3 pages in Q&A format
- Answer 10 questions on Reddit
For a complete framework, read our guide on how to get your brand into AI answers and whether you need to adapt to AI search in 2026.
Source: HumanReach.ai — Helping brands become trusted sources in the AI search landscape.
This article is part of the HumanReach.ai Resource Hub.
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About the author: This guide was created by HumanReach.ai, an organic growth agency that helps local and global businesses thrive in the AI Search Reality. Visit HumanReach.ai to learn more.
