{
  "name": "IT Master AI Citation Index",
  "url": "https://itmaster.uk/research/ai-citation-index",
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "attribution": "IT Master — https://itmaster.uk",
  "method": "Each week a fixed, published basket of questions is asked verbatim to ChatGPT (OpenAI API, gpt-5-mini, web search required on every question) and to Perplexity (Agent API, which always searches). Every source URL the answer cites is recorded and reduced to a registrable domain. Share = the percentage of answers in which a domain was cited at least once, not the share of links. The index measures whom each assistant cites when it searches, not how often it chooses to. Our own domain is measured on the same footing as every other and is never excluded or promoted.",
  "weeks": [
    {
      "week": "2026-09-28",
      "answers": 48,
      "uncited": 1,
      "errors": 0,
      "domains": 180,
      "top5_concentration": 45.8
    },
    {
      "week": "2026-10-05",
      "answers": 48,
      "uncited": 1,
      "errors": 0,
      "domains": 162,
      "top5_concentration": 43.8
    },
    {
      "week": "2026-10-12",
      "answers": 48,
      "uncited": 0,
      "errors": 0,
      "domains": 176,
      "top5_concentration": 39.6
    }
  ],
  "engines": {
    "overall": {
      "answers": 48,
      "asked": 48,
      "uncited": 0,
      "errors": 0,
      "domains": 176,
      "partial": false,
      "partial_reason": null,
      "table": [
        {
          "domain": "semrush.com",
          "answers_citing": 8,
          "share": 16.7,
          "previous_share": 12.5,
          "change": 4.2,
          "new": false
        },
        {
          "domain": "ahrefs.com",
          "answers_citing": 8,
          "share": 16.7,
          "previous_share": 20.8,
          "change": -4.1,
          "new": false
        },
        {
          "domain": "searchengineland.com",
          "answers_citing": 6,
          "share": 12.5,
          "previous_share": 8.3,
          "change": 4.2,
          "new": false
        },
        {
          "domain": "hubspot.com",
          "answers_citing": 5,
          "share": 10.4,
          "previous_share": 18.8,
          "change": -8.4,
          "new": false
        },
        {
          "domain": "arxiv.org",
          "answers_citing": 5,
          "share": 10.4,
          "previous_share": 8.3,
          "change": 2.1,
          "new": false
        },
        {
          "domain": "seo.com",
          "answers_citing": 5,
          "share": 10.4,
          "previous_share": 6.2,
          "change": 4.2,
          "new": false
        },
        {
          "domain": "reddit.com",
          "answers_citing": 4,
          "share": 8.3,
          "previous_share": 8.3,
          "change": 0,
          "new": false
        },
        {
          "domain": "surferseo.com",
          "answers_citing": 4,
          "share": 8.3,
          "previous_share": 2.1,
          "change": 6.2,
          "new": false
        },
        {
          "domain": "ai-search-tools.com",
          "answers_citing": 3,
          "share": 6.2,
          "previous_share": 6.2,
          "change": 0,
          "new": false
        },
        {
          "domain": "wikipedia.org",
          "answers_citing": 3,
          "share": 6.2,
          "previous_share": 6.2,
          "change": 0,
          "new": false
        },
        {
          "domain": "techradar.com",
          "answers_citing": 3,
          "share": 6.2,
          "previous_share": 2.1,
          "change": 4.1,
          "new": false
        },
        {
          "domain": "rank.ai",
          "answers_citing": 3,
          "share": 6.2,
          "previous_share": 0,
          "change": 6.2,
          "new": true
        },
        {
          "domain": "searchable.com",
          "answers_citing": 3,
          "share": 6.2,
          "previous_share": 4.2,
          "change": 2,
          "new": false
        },
        {
          "domain": "chrome.com",
          "answers_citing": 2,
          "share": 4.2,
          "previous_share": 2.1,
          "change": 2.1,
          "new": false
        },
        {
          "domain": "answerline.dev",
          "answers_citing": 2,
          "share": 4.2,
          "previous_share": 2.1,
          "change": 2.1,
          "new": false
        },
        {
          "domain": "llmpulse.ai",
          "answers_citing": 2,
          "share": 4.2,
          "previous_share": 2.1,
          "change": 2.1,
          "new": false
        },
        {
          "domain": "frase.io",
          "answers_citing": 2,
          "share": 4.2,
          "previous_share": 6.2,
          "change": -2,
          "new": false
        },
        {
          "domain": "astroseoblog.com",
          "answers_citing": 2,
          "share": 4.2,
          "previous_share": 2.1,
          "change": 2.1,
          "new": false
        },
        {
          "domain": "subscribepr.com",
          "answers_citing": 2,
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          "previous_share": 2.1,
          "change": 2.1,
          "new": false
        },
        {
          "domain": "prismic.io",
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          "previous_share": 2.1,
          "change": 2.1,
          "new": false
        },
        {
          "domain": "seotakeoff.com",
          "answers_citing": 2,
          "share": 4.2,
          "previous_share": 0,
          "change": 4.2,
          "new": true
        },
        {
          "domain": "google.cn",
          "answers_citing": 2,
          "share": 4.2,
          "previous_share": 2.1,
          "change": 2.1,
          "new": false
        },
        {
          "domain": "trakkr.ai",
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          "previous_share": 0,
          "change": 2.1,
          "new": true
        },
        {
          "domain": "enginely.ai",
          "answers_citing": 1,
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          "previous_share": 0,
          "change": 2.1,
          "new": true
        },
        {
          "domain": "frontiersin.org",
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          "previous_share": 0,
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          "new": true
        },
        {
          "domain": "marqops.com",
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        },
        {
          "domain": "aclanthology.org",
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        {
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        },
        {
          "domain": "busyworth.com",
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          "previous_share": 0,
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        },
        {
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          "answers_citing": 1,
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          "change": 0,
          "new": false
        },
        {
          "domain": "airops.com",
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        },
        {
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        {
          "domain": "awstatic.com",
          "answers_citing": 1,
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          "new": true
        },
        {
          "domain": "jasper.ai",
          "answers_citing": 1,
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          "previous_share": 0,
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        },
        {
          "domain": "pikaseo.com",
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        },
        {
          "domain": "pagerefresh.io",
          "answers_citing": 1,
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        },
        {
          "domain": "keywordgraph.com",
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        {
          "domain": "besthunt.ai",
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        {
          "domain": "commoncrawl.org",
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        }
      ]
    },
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      "asked": 24,
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      "errors": 0,
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      "partial": false,
      "partial_reason": null,
      "table": [
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        {
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        {
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        {
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        },
        {
          "domain": "wikipedia.org",
          "answers_citing": 3,
          "share": 12.5,
          "previous_share": 12.5,
          "change": 0,
          "new": false
        },
        {
          "domain": "rank.ai",
          "answers_citing": 3,
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          "new": true
        },
        {
          "domain": "answerline.dev",
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          "share": 8.3,
          "previous_share": 4.2,
          "change": 4.1,
          "new": false
        },
        {
          "domain": "techradar.com",
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        },
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          "change": 0,
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        },
        {
          "domain": "google.cn",
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        },
        {
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        },
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      ]
    },
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      "asked": 24,
      "uncited": 0,
      "errors": 0,
      "domains": 78,
      "partial": false,
      "partial_reason": null,
      "table": [
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        },
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        },
        {
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        },
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        {
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          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 4.2,
          "change": 0,
          "new": false
        },
        {
          "domain": "lenvanderhof.com",
          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 0,
          "change": 4.2,
          "new": true
        },
        {
          "domain": "digijaws.com",
          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 0,
          "change": 4.2,
          "new": true
        },
        {
          "domain": "seomatic.ai",
          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 4.2,
          "change": 0,
          "new": false
        },
        {
          "domain": "seoworks.co.uk",
          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 0,
          "change": 4.2,
          "new": true
        },
        {
          "domain": "byword.ai",
          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 0,
          "change": 4.2,
          "new": true
        },
        {
          "domain": "getellipsis.com",
          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 0,
          "change": 4.2,
          "new": true
        },
        {
          "domain": "albato.com",
          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 0,
          "change": 4.2,
          "new": true
        },
        {
          "domain": "techradar.com",
          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 0,
          "change": 4.2,
          "new": true
        },
        {
          "domain": "spawned.com",
          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 0,
          "change": 4.2,
          "new": true
        },
        {
          "domain": "victorious.com",
          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 4.2,
          "change": 0,
          "new": false
        },
        {
          "domain": "moz.com",
          "answers_citing": 1,
          "share": 4.2,
          "previous_share": 8.3,
          "change": -4.1,
          "new": false
        }
      ]
    }
  },
  "basket": [
    "best AI SEO tools",
    "best AI SEO agency",
    "what is generative engine optimization",
    "what is answer engine optimization",
    "how to get cited by ChatGPT",
    "how to rank in Google AI Overviews",
    "best AI content writing tools for SEO",
    "SEO automation software",
    "how to track AI search visibility",
    "does Google penalise AI generated content",
    "best LLM SEO tools",
    "how to measure brand mentions in ChatGPT",
    "AI SEO tools for agencies",
    "what is llms.txt",
    "should I block GPTBot",
    "how to write content that AI assistants cite",
    "programmatic SEO tools",
    "how to build topical authority",
    "AI content detection accuracy",
    "best alternative to Surfer SEO",
    "how much does AI content cost",
    "E-E-A-T for AI generated content",
    "answer engine optimization services",
    "AI visibility tracking tools"
  ],
  "basket_version": 2,
  "latest_week": "2026-10-12",
  "total_answers": 48,
  "note": "Share = the percentage of answers in which a domain was cited at least once, for a fixed published basket of questions asked verbatim. Both engines search the web on every question: Perplexity through its Agent API, which always searches, and ChatGPT through OpenAI's API (gpt-5-mini) with web search required. The index measures whom each assistant cites when it searches, not how often it chooses to: the ChatGPT app sometimes answers questions like these from memory and shows no sources. Every answer counts, including one that searched and cited no source ('uncited'); a probe that could not be measured is left out of both sides of the share and counted under 'errors', never as a zero, and a week in which an engine answered fewer than 90% of the questions is marked partial and shows no movement. Our own domain is measured on the same footing as every other and is never excluded or promoted. Series 2 began when Perplexity retired its Sonar API in September 2026: a Perplexity source counts only when the answer cites it, and ChatGPT must search. Its first week (28 Sep 2026) was re-measured within that week after the first run let ChatGPT skip search on 12 of 24 questions; that run is archived. Series 1 counted Perplexity's whole source list and left uncited answers out of the total, so the two series are never compared."
}