{
 "study": "s23",
 "version": "2.0",
 "collected": "2026-09-26 (answers, Google top 10); 2026-09-28 (Google top 100)",
 "statistics": {
  "version": "2.0",
  "answers_collected": "2026-09-26",
  "google_question_top10_collected": "2026-09-26",
  "google_top100_collected": "2026-09-28",
  "questions": 80,
  "citations": 2492,
  "keywords_collected_top100": 576,
  "keywords_missing": [
   "site:insurance.bcbsma.com physical therapy Boston preferred providers"
  ],
  "search_query_counts": {
   "claude_same_answer": 61,
   "claude_answers_with_a_search": 61,
   "chatgpt_proxy": 296,
   "gemini_proxy": 152
  },
  "bootstrap": {
   "unit": "question",
   "resamples": 10000,
   "seed": 23,
   "interval": "95% percentile"
  },
  "top100_coverage": {
   "keywords": 576,
   "partial_results_pct": 2.4,
   "median_deepest_rank": 73.5,
   "keywords_reaching_rank_50_pct": 69.6,
   "questions_median_deepest_rank": 63.5
  },
  "google_drift_top10_2026_09_26_vs_2026_09_28": {
   "questions": 80,
   "mean_jaccard": 0.44,
   "median_jaccard": 0.58
  },
  "by_engine": {
   "chatgpt": {
    "answers": 80,
    "answers_with_citations": 80,
    "citations": 384,
    "median_citations_per_answer_with_citations": 4.5,
    "answers_citing_top10_page_of_all_80": {
     "pct": 32.5,
     "lo": 22.5,
     "hi": 42.5
    },
    "answers_citing_top10_page_of_answers_with_citations": {
     "pct": 32.5,
     "lo": 22.5,
     "hi": 42.5
    },
    "citations_page_in_top10": {
     "pct": 8.3,
     "lo": 5.6,
     "hi": 11.3
    },
    "citations_site_in_top10": {
     "pct": 22.9,
     "lo": 17.1,
     "hi": 29.2
    },
    "first3_citations_page_in_top10": {
     "pct": 8.3,
     "lo": 5.1,
     "hi": 12.1
    },
    "rank_weighted_score_x100": {
     "pct": 4.7,
     "lo": 2.9,
     "hi": 6.8
    },
    "citations_page_in_top10_google_2026_09_28": 5.2,
    "citations_page_in_top100_question": {
     "pct": 10.7,
     "lo": 7.0,
     "hi": 14.8
    },
    "pathway_pct": {
     "A": {
      "pct": 8.3,
      "lo": 5.7,
      "hi": 11.3
     },
     "B": {
      "pct": 10.2,
      "lo": 6.5,
      "hi": 14.4
     },
     "C": {
      "pct": 13.0,
      "lo": 9.0,
      "hi": 17.7
     },
     "D": {
      "pct": 68.5,
      "lo": 61.7,
      "hi": 74.9
     }
    },
    "pathway_n": {
     "A": 32,
     "B": 39,
     "C": 50,
     "D": 263
    },
    "search_queries": "proxy from a separate API run",
    "site_only_pct": 14.6,
    "top10_via_searches_by_source_pct": {
     "chatgpt_proxy": 13.8,
     "gemini_proxy": 9.4,
     "claude": 4.2
    },
    "top10_question_or_own_searches": {
     "pct": 18.5,
     "lo": 14.0,
     "hi": 23.2
    },
    "by_locality": {
     "national": {
      "citations": 290,
      "questions": 56,
      "page_in_top10": {
       "pct": 8.3,
       "lo": 5.1,
       "hi": 11.8
      }
     },
     "city": {
      "citations": 72,
      "questions": 19,
      "page_in_top10": {
       "pct": 11.1,
       "lo": 4.8,
       "hi": 18.3
      }
     },
     "travel destination": {
      "citations": 15,
      "questions": 4,
      "page_in_top10": {
       "pct": 0.0,
       "lo": 0.0,
       "hi": 0.0
      }
     },
     "state": {
      "citations": 7,
      "questions": 1,
      "page_in_top10": {
       "pct": 0.0,
       "lo": 0.0,
       "hi": 0.0
      }
     }
    },
    "local_minus_national_points": {
     "pct": 0.2,
     "lo": -6.0,
     "hi": 7.1
    },
    "v1_rule_local_pct": 8.5,
    "v1_rule_national_pct": 8.3
   },
   "gemini": {
    "answers": 80,
    "answers_with_citations": 73,
    "citations": 259,
    "median_citations_per_answer_with_citations": 3,
    "answers_citing_top10_page_of_all_80": {
     "pct": 36.2,
     "lo": 26.2,
     "hi": 47.5
    },
    "answers_citing_top10_page_of_answers_with_citations": {
     "pct": 39.7,
     "lo": 28.8,
     "hi": 51.4
    },
    "citations_page_in_top10": {
     "pct": 16.6,
     "lo": 11.3,
     "hi": 22.2
    },
    "citations_site_in_top10": {
     "pct": 23.6,
     "lo": 17.4,
     "hi": 30.0
    },
    "first3_citations_page_in_top10": {
     "pct": 16.3,
     "lo": 11.1,
     "hi": 21.9
    },
    "rank_weighted_score_x100": {
     "pct": 9.9,
     "lo": 6.9,
     "hi": 13.2
    },
    "citations_page_in_top10_google_2026_09_28": 15.1,
    "citations_page_in_top100_question": {
     "pct": 27.4,
     "lo": 19.5,
     "hi": 36.0
    },
    "pathway_pct": {
     "A": {
      "pct": 16.6,
      "lo": 11.3,
      "hi": 22.2
     },
     "B": {
      "pct": 13.5,
      "lo": 8.8,
      "hi": 18.8
     },
     "C": {
      "pct": 20.1,
      "lo": 14.3,
      "hi": 26.2
     },
     "D": {
      "pct": 49.8,
      "lo": 40.8,
      "hi": 58.8
     }
    },
    "pathway_n": {
     "A": 43,
     "B": 35,
     "C": 52,
     "D": 129
    },
    "search_queries": "proxy from a separate API run",
    "site_only_pct": 6.9,
    "top10_via_searches_by_source_pct": {
     "chatgpt_proxy": 15.8,
     "gemini_proxy": 19.7,
     "claude": 9.3
    },
    "top10_question_or_own_searches": {
     "pct": 30.1,
     "lo": 23.6,
     "hi": 36.8
    },
    "by_locality": {
     "national": {
      "citations": 176,
      "questions": 51,
      "page_in_top10": {
       "pct": 21.6,
       "lo": 15.1,
       "hi": 28.1
      }
     },
     "city": {
      "citations": 72,
      "questions": 19,
      "page_in_top10": {
       "pct": 6.9,
       "lo": 0.0,
       "hi": 18.4
      }
     },
     "travel destination": {
      "citations": 6,
      "questions": 2,
      "page_in_top10": {
       "pct": 0.0,
       "lo": 0.0,
       "hi": 0.0
      }
     },
     "state": {
      "citations": 5,
      "questions": 1,
      "page_in_top10": {
       "pct": 0.0,
       "lo": 0.0,
       "hi": 0.0
      }
     }
    },
    "local_minus_national_points": {
     "pct": -15.6,
     "lo": -25.1,
     "hi": -4.2
    },
    "v1_rule_local_pct": 6.0,
    "v1_rule_national_pct": 21.6
   },
   "perplexity": {
    "answers": 80,
    "answers_with_citations": 80,
    "citations": 1588,
    "median_citations_per_answer_with_citations": 20.0,
    "answers_citing_top10_page_of_all_80": {
     "pct": 78.8,
     "lo": 68.8,
     "hi": 87.5
    },
    "answers_citing_top10_page_of_answers_with_citations": {
     "pct": 78.8,
     "lo": 68.8,
     "hi": 87.5
    },
    "citations_page_in_top10": {
     "pct": 14.2,
     "lo": 11.9,
     "hi": 16.6
    },
    "citations_site_in_top10": {
     "pct": 26.5,
     "lo": 23.0,
     "hi": 30.2
    },
    "first3_citations_page_in_top10": {
     "pct": 23.8,
     "lo": 18.3,
     "hi": 29.2
    },
    "rank_weighted_score_x100": {
     "pct": 9.7,
     "lo": 7.8,
     "hi": 11.5
    },
    "citations_page_in_top10_google_2026_09_28": 12.0,
    "citations_page_in_top100_question": {
     "pct": 28.1,
     "lo": 22.5,
     "hi": 33.8
    },
    "pathway_pct": {
     "A": {
      "pct": 14.2,
      "lo": 12.0,
      "hi": 16.6
     },
     "B": {
      "pct": 0.0,
      "lo": 0.0,
      "hi": 0.0
     },
     "C": {
      "pct": 19.0,
      "lo": 14.9,
      "hi": 23.3
     },
     "D": {
      "pct": 66.8,
      "lo": 62.0,
      "hi": 71.5
     }
    },
    "pathway_n": {
     "A": 226,
     "B": 0,
     "C": 301,
     "D": 1061
    },
    "search_queries": "not available",
    "site_only_pct": 12.3,
    "by_locality": {
     "national": {
      "citations": 1130,
      "questions": 56,
      "page_in_top10": {
       "pct": 14.7,
       "lo": 11.8,
       "hi": 17.7
      }
     },
     "city": {
      "citations": 370,
      "questions": 19,
      "page_in_top10": {
       "pct": 15.1,
       "lo": 11.1,
       "hi": 19.0
      }
     },
     "travel destination": {
      "citations": 70,
      "questions": 4,
      "page_in_top10": {
       "pct": 5.7,
       "lo": 0.0,
       "hi": 11.8
      }
     },
     "state": {
      "citations": 18,
      "questions": 1,
      "page_in_top10": {
       "pct": 0.0,
       "lo": 0.0,
       "hi": 0.0
      }
     }
    },
    "local_minus_national_points": {
     "pct": -1.6,
     "lo": -6.3,
     "hi": 3.0
    },
    "v1_rule_local_pct": 13.1,
    "v1_rule_national_pct": 14.7
   },
   "claude": {
    "answers": 80,
    "answers_with_citations": 61,
    "citations": 261,
    "median_citations_per_answer_with_citations": 4,
    "answers_citing_top10_page_of_all_80": {
     "pct": 46.2,
     "lo": 35.0,
     "hi": 57.5
    },
    "answers_citing_top10_page_of_answers_with_citations": {
     "pct": 60.7,
     "lo": 48.3,
     "hi": 72.9
    },
    "citations_page_in_top10": {
     "pct": 25.7,
     "lo": 19.4,
     "hi": 32.0
    },
    "citations_site_in_top10": {
     "pct": 32.2,
     "lo": 25.8,
     "hi": 38.7
    },
    "first3_citations_page_in_top10": {
     "pct": 22.9,
     "lo": 16.9,
     "hi": 29.1
    },
    "rank_weighted_score_x100": {
     "pct": 15.6,
     "lo": 11.5,
     "hi": 20.0
    },
    "citations_page_in_top10_google_2026_09_28": 23.4,
    "citations_page_in_top100_question": {
     "pct": 37.2,
     "lo": 27.8,
     "hi": 46.4
    },
    "pathway_pct": {
     "A": {
      "pct": 25.7,
      "lo": 19.4,
      "hi": 32.2
     },
     "B": {
      "pct": 10.0,
      "lo": 4.8,
      "hi": 15.8
     },
     "C": {
      "pct": 27.6,
      "lo": 20.7,
      "hi": 34.9
     },
     "D": {
      "pct": 36.8,
      "lo": 28.8,
      "hi": 44.8
     }
    },
    "pathway_n": {
     "A": 67,
     "B": 26,
     "C": 72,
     "D": 96
    },
    "search_queries": "same answers",
    "site_only_pct": 6.5,
    "top10_via_searches_by_source_pct": {
     "chatgpt_proxy": 25.3,
     "gemini_proxy": 29.1,
     "claude": 24.5
    },
    "top10_question_or_own_searches": {
     "pct": 35.6,
     "lo": 28.4,
     "hi": 42.9
    },
    "by_locality": {
     "national": {
      "citations": 158,
      "questions": 40,
      "page_in_top10": {
       "pct": 20.9,
       "lo": 14.4,
       "hi": 27.6
      }
     },
     "city": {
      "citations": 84,
      "questions": 17,
      "page_in_top10": {
       "pct": 35.7,
       "lo": 24.1,
       "hi": 47.3
      }
     },
     "travel destination": {
      "citations": 14,
      "questions": 3,
      "page_in_top10": {
       "pct": 28.6,
       "lo": 0.0,
       "hi": 80.0
      }
     },
     "state": {
      "citations": 5,
      "questions": 1,
      "page_in_top10": {
       "pct": 0.0,
       "lo": 0.0,
       "hi": 0.0
      }
     }
    },
    "local_minus_national_points": {
     "pct": 12.1,
     "lo": -1.3,
     "hi": 25.8
    },
    "v1_rule_local_pct": 33.0,
    "v1_rule_national_pct": 20.9
   }
  },
  "engine_differences_points": {
   "chatgpt_minus_gemini": {
    "answers_citing_top10_of_all_80": {
     "pct": -3.7,
     "lo": -15.0,
     "hi": 7.5
    },
    "citations_page_in_top10": {
     "pct": -8.3,
     "lo": -14.0,
     "hi": -2.9
    },
    "first3_citations_page_in_top10": {
     "pct": -8.0,
     "lo": -14.1,
     "hi": -2.4
    }
   },
   "chatgpt_minus_perplexity": {
    "answers_citing_top10_of_all_80": {
     "pct": -46.2,
     "lo": -57.5,
     "hi": -35.0
    },
    "citations_page_in_top10": {
     "pct": -5.9,
     "lo": -8.8,
     "hi": -2.8
    },
    "first3_citations_page_in_top10": {
     "pct": -15.5,
     "lo": -20.3,
     "hi": -10.7
    }
   },
   "chatgpt_minus_claude": {
    "answers_citing_top10_of_all_80": {
     "pct": -13.8,
     "lo": -27.5,
     "hi": 0.0
    },
    "citations_page_in_top10": {
     "pct": -17.3,
     "lo": -24.0,
     "hi": -10.9
    },
    "first3_citations_page_in_top10": {
     "pct": -14.6,
     "lo": -21.2,
     "hi": -8.2
    }
   },
   "gemini_minus_perplexity": {
    "answers_citing_top10_of_all_80": {
     "pct": -42.5,
     "lo": -53.8,
     "hi": -31.2
    },
    "citations_page_in_top10": {
     "pct": 2.4,
     "lo": -2.7,
     "hi": 7.7
    },
    "first3_citations_page_in_top10": {
     "pct": -7.4,
     "lo": -13.5,
     "hi": -1.2
    }
   },
   "gemini_minus_claude": {
    "answers_citing_top10_of_all_80": {
     "pct": -10.0,
     "lo": -25.0,
     "hi": 6.2
    },
    "citations_page_in_top10": {
     "pct": -9.1,
     "lo": -17.5,
     "hi": -0.4
    },
    "first3_citations_page_in_top10": {
     "pct": -6.6,
     "lo": -14.9,
     "hi": 1.6
    }
   },
   "perplexity_minus_claude": {
    "answers_citing_top10_of_all_80": {
     "pct": 32.5,
     "lo": 22.5,
     "hi": 43.7
    },
    "citations_page_in_top10": {
     "pct": -11.4,
     "lo": -17.6,
     "hi": -5.6
    },
    "first3_citations_page_in_top10": {
     "pct": 0.8,
     "lo": -6.7,
     "hi": 8.2
    }
   }
  },
  "candidate_model": {
   "unit": "Google top-10 page for the question as typed (2026-09-26) x engine, answers with citations only",
   "outcome": "the engine's answer cites the page",
   "predictors": "log2 of Google rank; for ChatGPT, Gemini and Claude also whether the page is in the top 10 for one of the engine's searches (Claude: same answer; others: proxy)",
   "method": "logistic GEE, independence working correlation, robust errors clustered by question",
   "by_engine": {
    "chatgpt": {
     "candidates": 684,
     "cited_pct": 4.7,
     "cited_pct_rank_1_3": 6.7,
     "cited_pct_rank_4_10": 3.6,
     "rank_only": {
      "log2_rank": {
       "odds_ratio": 0.63,
       "lo": 0.44,
       "hi": 0.92,
       "p": 0.0156
      }
     },
     "rank_and_own_search_top10": {
      "log2_rank": {
       "odds_ratio": 0.93,
       "lo": 0.55,
       "hi": 1.57,
       "p": 0.7931
      },
      "top10_own_search": {
       "odds_ratio": 5.93,
       "lo": 2.01,
       "hi": 17.48,
       "p": 0.0012
      }
     },
     "candidates_with_search": 509,
     "own_search_top10_share_of_candidates_pct": 33.2
    },
    "gemini": {
     "candidates": 621,
     "cited_pct": 6.9,
     "cited_pct_rank_1_3": 6.8,
     "cited_pct_rank_4_10": 7.0,
     "rank_only": {
      "log2_rank": {
       "odds_ratio": 0.97,
       "lo": 0.69,
       "hi": 1.36,
       "p": 0.844
      }
     },
     "rank_and_own_search_top10": {
      "log2_rank": {
       "odds_ratio": 0.98,
       "lo": 0.68,
       "hi": 1.41,
       "p": 0.9
      },
      "top10_own_search": {
       "odds_ratio": 1.22,
       "lo": 0.55,
       "hi": 2.72,
       "p": 0.618
      }
     },
     "candidates_with_search": 604,
     "own_search_top10_share_of_candidates_pct": 35.4
    },
    "perplexity": {
     "candidates": 684,
     "cited_pct": 33.0,
     "cited_pct_rank_1_3": 40.8,
     "cited_pct_rank_4_10": 28.8,
     "rank_only": {
      "log2_rank": {
       "odds_ratio": 0.74,
       "lo": 0.64,
       "hi": 0.86,
       "p": 0.0001
      }
     }
    },
    "claude": {
     "candidates": 523,
     "cited_pct": 12.8,
     "cited_pct_rank_1_3": 20.2,
     "cited_pct_rank_4_10": 8.8,
     "rank_only": {
      "log2_rank": {
       "odds_ratio": 0.65,
       "lo": 0.5,
       "hi": 0.83,
       "p": 0.0008
      }
     },
     "rank_and_own_search_top10": {
      "log2_rank": {
       "odds_ratio": 0.69,
       "lo": 0.53,
       "hi": 0.9,
       "p": 0.0055
      },
      "top10_own_search": {
       "odds_ratio": 2.25,
       "lo": 1.18,
       "hi": 4.31,
       "p": 0.0141
      }
     },
     "candidates_with_search": 523,
     "own_search_top10_share_of_candidates_pct": 36.9
    }
   }
  },
  "locality_counts": {
   "travel destination": 4,
   "city": 19,
   "national": 56,
   "state": 1
  },
  "reference_ai_overviews_url_in_top10_pct": 28.7,
  "bing_discarded": {
   "reason": "Bing SERP returned unrelated results (e.g. melamine resin, Buckingham Palace) for buyer questions; retested with location_name/device and a short keyword with the same result",
   "bing_requests_discarded": 80,
   "interpretation": "Says nothing about whether any assistant uses Bing."
  }
 }
}