{
 "study": "s18",
 "version": "1.0",
 "collected": "2026-09-26",
 "statistics": {
  "collected": "2026-09-26",
  "answers": 238,
  "questions": 20,
  "unfinished_answers_excluded": [
   {
    "engine": "chatgpt",
    "prompt": "What is the best robot vacuum on a tight budget?",
    "country": null,
    "variant": "budget",
    "text": "I’ll compare current budget robot-vacuum options, focusing on price, cleaning performance, navigation, and whether you’re getting useful features for the money."
   },
   {
    "engine": "chatgpt",
    "prompt": "What are the best noise-cancelling headphones on a tight budget?",
    "country": null,
    "variant": "budget",
    "text": "I’ll compare current budget options by price, noise cancellation, comfort, and battery life, with an emphasis on genuinely inexpensive models."
   }
  ],
  "by_engine": {
   "chatgpt": {
    "by_variant": {
     "context": {
      "n": 20,
      "mean_jaccard_vs_original": 0.402,
      "same_first_brand_pct": 40.0,
      "mean_share_of_brands_new": 37.1,
      "same_first_n": 20
     },
     "budget": {
      "n": 18,
      "mean_jaccard_vs_original": 0.454,
      "same_first_brand_pct": 11.1,
      "mean_share_of_brands_new": 37.7,
      "same_first_n": 18
     },
     "conversational": {
      "n": 20,
      "mean_jaccard_vs_original": 0.605,
      "same_first_brand_pct": 65.0,
      "mean_share_of_brands_new": 28.9,
      "same_first_n": 20
     }
    },
    "run_to_run_baseline_jaccard_study8": 0.53,
    "mean_jaccard_all_variants": 0.487
   },
   "gemini": {
    "by_variant": {
     "context": {
      "n": 20,
      "mean_jaccard_vs_original": 0.365,
      "same_first_brand_pct": 30.0,
      "mean_share_of_brands_new": 44.4,
      "same_first_n": 20
     },
     "budget": {
      "n": 20,
      "mean_jaccard_vs_original": 0.292,
      "same_first_brand_pct": 15.0,
      "mean_share_of_brands_new": 53.9,
      "same_first_n": 20
     },
     "conversational": {
      "n": 20,
      "mean_jaccard_vs_original": 0.473,
      "same_first_brand_pct": 35.0,
      "mean_share_of_brands_new": 38.4,
      "same_first_n": 20
     }
    },
    "run_to_run_baseline_jaccard_study8": 0.421,
    "mean_jaccard_all_variants": 0.377
   },
   "perplexity": {
    "by_variant": {
     "context": {
      "n": 20,
      "mean_jaccard_vs_original": 0.47,
      "same_first_brand_pct": 50.0,
      "mean_share_of_brands_new": 32.7,
      "same_first_n": 20
     },
     "budget": {
      "n": 20,
      "mean_jaccard_vs_original": 0.353,
      "same_first_brand_pct": 10.0,
      "mean_share_of_brands_new": 42.7,
      "same_first_n": 20
     },
     "conversational": {
      "n": 20,
      "mean_jaccard_vs_original": 0.645,
      "same_first_brand_pct": 65.0,
      "mean_share_of_brands_new": 27.6,
      "same_first_n": 20
     }
    },
    "run_to_run_baseline_jaccard_study8": 0.682,
    "mean_jaccard_all_variants": 0.489
   }
  },
  "matched_baseline": {
   "questions": 5,
   "chatgpt": {
    "repeat_runs_jaccard": 0.678,
    "context_jaccard": 0.475,
    "budget_jaccard": 0.374,
    "conversational_jaccard": 0.454
   },
   "gemini": {
    "repeat_runs_jaccard": 0.427,
    "context_jaccard": 0.333,
    "budget_jaccard": 0.292,
    "conversational_jaccard": 0.426
   },
   "perplexity": {
    "repeat_runs_jaccard": 0.626,
    "context_jaccard": 0.55,
    "budget_jaccard": 0.349,
    "conversational_jaccard": 0.639
   }
  },
  "average_across_engines": {
   "context": {
    "mean_jaccard_vs_original": 0.412,
    "same_first_brand_pct": 40.0
   },
   "budget": {
    "mean_jaccard_vs_original": 0.366,
    "same_first_brand_pct": 12.0
   },
   "conversational": {
    "mean_jaccard_vs_original": 0.574,
    "same_first_brand_pct": 55.0
   }
  }
 }
}