ChatGPT vs Perplexity: Why They Cite Completely Different Sources (2026 Per-Engine AEO Guide)

At a glance: ChatGPT and Perplexity agree on almost nothing. Across 100,000 identical prompts, only 11% of cited domains appeared in both engines. ChatGPT leans on authoritative reference and editorial sources; Perplexity leans heavily on Reddit and community content. One generic "AI optimisation" strategy cannot win both — you need a per-engine AEO plan, measured per engine.

What this covers

• The headline number: 11% overlap, two separate ecosystems
• ChatGPT vs Perplexity vs Google AI Overviews: citation behaviour compared
• Why the engines diverge: three mechanical reasons
• 1. Different retrieval pipelines, different shortlists
• 2. Different freshness appetites
• 3. Different definitions of trust

This is a technical summary. The full guide — with the data, tables and worked examples — is on our site: *ChatGPT vs Perplexity: Why They Cite Completely Different Sources (2026 Per-Engine AEO Guide)*.

LeadsNow AI builds pay-per-result AI lead generation and answer-engine-optimisation systems in Australia.