{
  "schema_version": "makeitby-bts-buffer-observations-v1",
  "study_period": {
    "start_month": "2022-01",
    "end_month": "2026-06",
    "months": 54
  },
  "provenance": {
    "verified_on": "2026-10-24",
    "research_commit": "7150623084ed413b0f990480bfad712ac0fb0d01",
    "source": "BTS Marketing Carrier On-Time Performance",
    "source_urls": [
      "https://www.transtats.bts.gov/TableInfo.asp?QO_fu146_anzr=b0-gvzr&gnoyr_VQ=FGK",
      "https://www.bts.gov/explore-topics-and-geography/modes/aviation/number-39-technical-directive-reporting-time"
    ],
    "pilot_script": "scripts/pilot_bts_deadline_buffer.py",
    "verification_script": "scripts/verify_bts_buffer_publication.py",
    "input_sha256": {
      "monthly_counts.csv": "5f9ce95e341c32e8122936b2762c1f847f36493566391fe5563563d3db9361c6",
      "pooled_curves.csv": "c68d408bb62ce50336648420c4df1cf9ea5e535ffb178c339fad04efdfe05603"
    }
  },
  "controls": {
    "source_rows": 33432890,
    "excluded_missing_physical_key": 1,
    "scheduled_operations": 33432889,
    "known_outcomes": 33432885,
    "unknown_outcomes": 4,
    "cancelled_operations": 591008,
    "diverted_operations": 85090,
    "standard_on_time_operations": 25826108,
    "diverted_reached_destination": 76780,
    "diverted_not_reached_destination": 8310,
    "unresolved_diversion_operations": 1
  },
  "methods": {
    "unit": "Identifiable scheduled physical operation, not passenger or marketing alias",
    "physical_key": [
      "FlightDate",
      "Operating_Airline",
      "Flight_Number_Operating_Airline",
      "Origin",
      "Dest",
      "CRSDepTime"
    ],
    "ordinary_success": "ArrDelay <= buffer_minutes",
    "diversion_success": "Reached scheduled destination and DivArrDelay <= buffer_minutes",
    "known_failures": "Cancellations and diversions not reaching scheduled destination",
    "unknown_outcomes": "Unresolved destination status or missing applicable arrival delay",
    "pooling": "Sum integer successes and known outcomes, never average monthly rates",
    "lower_bound": "successful_arrivals / scheduled_operations",
    "upper_bound": "(successful_arrivals + unknown_outcomes) / scheduled_operations",
    "bounds_interpretation": "Unknown-outcome completion bounds, not confidence intervals",
    "conventional_on_time": "Ordinary noncancelled, nondiverted ArrDelay < 15",
    "missing_key_exclusion": {
      "month": "2024-08",
      "records": 1,
      "reason": "Missing operating flight number prevents safe physical identification"
    },
    "scope": "Reported domestic nonstop operations including regional codeshare partners",
    "limitations": [
      "Reporting coverage is not every U.S. flight and may change over time",
      "Operation-weighted pooling does not adjust route, carrier, season or arrival-time mix",
      "Correlated operations are not independent trials for future-flight inference",
      "Observed cumulative thresholds do not identify a causal passenger buffer effect",
      "No individual-flight prediction, passenger reaccommodation or ground travel outcome",
      "Separate from MakeItBy frozen predictive model and its validation population"
    ]
  },
  "rows": [
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      "months": 54,
      "scheduled_operations": 33432889,
      "source_rows": 33432890,
      "excluded_missing_physical_key": 1,
      "known_outcomes": 33432885,
      "unknown_outcomes": 4,
      "successful_arrivals": 20755427,
      "known_outcome_success_fraction": 0.6208087336764386,
      "lower_bound_all_scheduled": 0.6208086594012261,
      "upper_bound_all_scheduled": 0.620808779043893
    },
    {
      "buffer_minutes": 15,
      "months": 54,
      "scheduled_operations": 33432889,
      "source_rows": 33432890,
      "excluded_missing_physical_key": 1,
      "known_outcomes": 33432885,
      "unknown_outcomes": 4,
      "successful_arrivals": 26048417,
      "known_outcome_success_fraction": 0.77912561240228,
      "lower_bound_all_scheduled": 0.7791255191856139,
      "upper_bound_all_scheduled": 0.7791256388282808
    },
    {
      "buffer_minutes": 30,
      "months": 54,
      "scheduled_operations": 33432889,
      "source_rows": 33432890,
      "excluded_missing_physical_key": 1,
      "known_outcomes": 33432885,
      "unknown_outcomes": 4,
      "successful_arrivals": 28345088,
      "known_outcome_success_fraction": 0.847820581442493,
      "lower_bound_all_scheduled": 0.8478204800069775,
      "upper_bound_all_scheduled": 0.8478205996496444
    },
    {
      "buffer_minutes": 60,
      "months": 54,
      "scheduled_operations": 33432889,
      "source_rows": 33432890,
      "excluded_missing_physical_key": 1,
      "known_outcomes": 33432885,
      "unknown_outcomes": 4,
      "successful_arrivals": 30364628,
      "known_outcome_success_fraction": 0.9082263765152184,
      "lower_bound_all_scheduled": 0.9082262678525928,
      "upper_bound_all_scheduled": 0.9082263874952595
    },
    {
      "buffer_minutes": 90,
      "months": 54,
      "scheduled_operations": 33432889,
      "source_rows": 33432890,
      "excluded_missing_physical_key": 1,
      "known_outcomes": 33432885,
      "unknown_outcomes": 4,
      "successful_arrivals": 31282432,
      "known_outcome_success_fraction": 0.935678509347907,
      "lower_bound_all_scheduled": 0.9356783974008348,
      "upper_bound_all_scheduled": 0.9356785170435017
    },
    {
      "buffer_minutes": 120,
      "months": 54,
      "scheduled_operations": 33432889,
      "source_rows": 33432890,
      "excluded_missing_physical_key": 1,
      "known_outcomes": 33432885,
      "unknown_outcomes": 4,
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      "lower_bound_all_scheduled": 0.9510068065012269,
      "upper_bound_all_scheduled": 0.9510069261438938
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    {
      "buffer_minutes": 180,
      "months": 54,
      "scheduled_operations": 33432889,
      "source_rows": 33432890,
      "excluded_missing_physical_key": 1,
      "known_outcomes": 33432885,
      "unknown_outcomes": 4,
      "successful_arrivals": 32317946,
      "known_outcome_success_fraction": 0.9666514271801551,
      "lower_bound_all_scheduled": 0.9666513115274005,
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  ]
}