This study shows that most web pages retrieved by ChatGPT are never cited at all, and other findings:

• Varies by category, but on average only 15% of the pages retrieved are cited
• Page title/query overlap matters
• Flesch Reading Ease scores of 50+ help
• Ranking #1 on Google helps
• 33% of cited pages come from fan-out, not the original query
• And much more

Takeaways:

• Write good page titles that include the primary search query
• Fan-out coverage matters, not just "target keywords" - think about fulfilling the full scope of the search intent implied by the primary query
• Check your Flesch Reading Ease score and aim for a high one (tons of apps/extensions for this, Hemingway Editor has a free one)
• When you refresh content, base it on fulfilling more adjacent queries to strengthen coverage of supporting topics