{
  "source": "NBP and ECB statistics; derived calculations by editorial team",
  "source_snapshot_date": "2026-10-07",
  "period": [
    "2025-01-01",
    "2025-12-31"
  ],
  "study_a": {
    "n_common_dates": 250,
    "mean_signed_bps": "-0.9313608035459101563267128703523360871409561642364",
    "median_signed_bps": "-1.0469658259485504316295643056647625506333215108500",
    "mean_absolute_bps": "16.814855626759196067269758624557081818290247556084",
    "median_absolute_bps": "12.082988967335327079346861299121976090523591168300",
    "minimum_signed_bps": "-66.405699252671524689777198333061718622680604381400",
    "minimum_date": "2025-04-11",
    "maximum_signed_bps": "72.768798313422347153900210822206605762473647224000",
    "maximum_date": "2025-04-08",
    "maximum_absolute_bps": "72.768798313422347153900210822206605762473647224000",
    "maximum_absolute_date": "2025-04-08",
    "positive_days": 122,
    "negative_days": 128,
    "zero_days": 0,
    "nbp_dates": 251,
    "ecb_usd_pln_dates_2025": 255,
    "nbp_only_dates": [
      "2025-04-18"
    ],
    "ecb_only_dates": [
      "2025-01-06",
      "2025-06-19",
      "2025-08-15",
      "2025-11-11",
      "2025-12-24"
    ],
    "unit": "basis points of NBP/ECB-implied ratio minus one; positive means NBP higher",
    "expression": "10000 * (NBP_PLN_per_USD * ECB_USD_per_EUR / ECB_PLN_per_EUR - 1)",
    "join": "same ISO publication date only; inner join; no forward filling or interpolation"
  },
  "hypothetical_case": {
    "ECB_USD_per_EUR": "1.25",
    "ECB_PLN_per_EUR": "5.00",
    "NBP_PLN_per_USD": [
      "4.0080",
      "3.9920"
    ],
    "signed_bps": [
      20,
      -20
    ],
    "mean_signed_bps": 0,
    "mean_absolute_bps": 20,
    "not_actual_data": true
  },
  "limits": [
    "Same publication date does not imply simultaneous observation or exact fixing time.",
    "Not executable Bid/Ask, arbitrage, spread, trading costs, broker fills or investment return.",
    "Pinned snapshots only; no historical first-vintage or website-uptime claim.",
    "No daily joined data or NBP raw responses distributed."
  ]
}