{
  "question_id": "W223",
  "slug": "cpi-category-falls-50-percent",
  "title": "A major consumer price category falls 50% from its peak",
  "type": "binary",
  "resolution": {
    "levels": [],
    "values": [],
    "annotations": []
  },
  "forecasts": [
    {
      "question_id": "W223",
      "forecast_date": "2026-09-20",
      "evidence_cutoff": "2026-09-20",
      "method": "wide-v2",
      "opened": "2026-09-16",
      "linked_questions": [],
      "reading_adopted": null,
      "summary": null,
      "ambiguities": [],
      "key_drivers": [],
      "would_update_on": [],
      "forecasts": [
        {
          "period_end": "2026-09-30",
          "p_yes": 0
        },
        {
          "period_end": "2026-12-31",
          "p_yes": 0.00005
        },
        {
          "period_end": "2027-03-31",
          "p_yes": 0.00015
        },
        {
          "period_end": "2027-06-30",
          "p_yes": 0.000275
        },
        {
          "period_end": "2027-09-30",
          "p_yes": 0.0004499
        },
        {
          "period_end": "2027-12-31",
          "p_yes": 0.0006498
        },
        {
          "period_end": "2028-03-31",
          "p_yes": 0.0008997
        },
        {
          "period_end": "2028-06-30",
          "p_yes": 0.0012494
        },
        {
          "period_end": "2028-09-30",
          "p_yes": 0.0016988
        },
        {
          "period_end": "2028-12-31",
          "p_yes": 0.0022479
        },
        {
          "period_end": "2029-03-31",
          "p_yes": 0.0028964
        },
        {
          "period_end": "2029-06-30",
          "p_yes": 0.0036442
        },
        {
          "period_end": "2029-09-30",
          "p_yes": 0.0044911
        },
        {
          "period_end": "2029-12-31",
          "p_yes": 0.0054369
        },
        {
          "period_end": "2030-03-31",
          "p_yes": 0.0064812
        },
        {
          "period_end": "2030-06-30",
          "p_yes": 0.0076237
        },
        {
          "period_end": "2030-09-30",
          "p_yes": 0.0088642
        },
        {
          "period_end": "2030-12-31",
          "p_yes": 0.0102022
        },
        {
          "period_end": "2031-03-31",
          "p_yes": 0.0116374
        },
        {
          "period_end": "2031-06-30",
          "p_yes": 0.0131694
        },
        {
          "period_end": "2031-09-30",
          "p_yes": 0.0147976
        }
      ],
      "passes": []
    },
    {
      "question_id": "W223",
      "forecast_date": "2026-09-27",
      "evidence_cutoff": "2026-09-27",
      "method": "wide-v2",
      "opened": "2026-09-16",
      "linked_questions": [],
      "reading_adopted": null,
      "summary": null,
      "ambiguities": [],
      "key_drivers": [],
      "would_update_on": [],
      "forecasts": [
        {
          "period_end": "2026-09-30",
          "p_yes": 0
        },
        {
          "period_end": "2026-12-31",
          "p_yes": 0.00005
        },
        {
          "period_end": "2027-03-31",
          "p_yes": 0.00013
        },
        {
          "period_end": "2027-06-30",
          "p_yes": 0.00023
        },
        {
          "period_end": "2027-09-30",
          "p_yes": 0.0003799
        },
        {
          "period_end": "2027-12-31",
          "p_yes": 0.0005799
        },
        {
          "period_end": "2028-03-31",
          "p_yes": 0.0008297
        },
        {
          "period_end": "2028-06-30",
          "p_yes": 0.0011295
        },
        {
          "period_end": "2028-09-30",
          "p_yes": 0.001529
        },
        {
          "period_end": "2028-12-31",
          "p_yes": 0.0020283
        },
        {
          "period_end": "2029-03-31",
          "p_yes": 0.002627
        },
        {
          "period_end": "2029-06-30",
          "p_yes": 0.0033252
        },
        {
          "period_end": "2029-09-30",
          "p_yes": 0.0042222
        },
        {
          "period_end": "2029-12-31",
          "p_yes": 0.0053176
        },
        {
          "period_end": "2030-03-31",
          "p_yes": 0.0066107
        },
        {
          "period_end": "2030-06-30",
          "p_yes": 0.0081007
        },
        {
          "period_end": "2030-09-30",
          "p_yes": 0.009787
        },
        {
          "period_end": "2030-12-31",
          "p_yes": 0.0116684
        },
        {
          "period_end": "2031-03-31",
          "p_yes": 0.0137439
        },
        {
          "period_end": "2031-06-30",
          "p_yes": 0.0160123
        },
        {
          "period_end": "2031-09-30",
          "p_yes": 0.0184722
        }
      ],
      "passes": []
    },
    {
      "question_id": "W223",
      "forecast_date": "2026-10-03",
      "evidence_cutoff": "2026-10-03",
      "method": "wide-v2.1",
      "opened": "2026-09-16",
      "linked_questions": [],
      "reading_adopted": "Any BLS-published NSA monthly value for the eight listed U.S. city average series counts (literal reading, so even a later-corrected erroneous value could qualify), while rebasings and missing observations do not; this only affects a tiny error-path tail.",
      "summary": null,
      "ambiguities": [],
      "key_drivers": [],
      "would_update_on": [],
      "forecasts": [
        {
          "period_end": "2026-12-31",
          "p_yes": 0.0001
        },
        {
          "period_end": "2027-03-31",
          "p_yes": 0.0002
        },
        {
          "period_end": "2027-06-30",
          "p_yes": 0.0003
        },
        {
          "period_end": "2027-09-30",
          "p_yes": 0.0004
        },
        {
          "period_end": "2027-12-31",
          "p_yes": 0.0005
        },
        {
          "period_end": "2028-03-31",
          "p_yes": 0.0006
        },
        {
          "period_end": "2028-06-30",
          "p_yes": 0.0008
        },
        {
          "period_end": "2028-09-30",
          "p_yes": 0.0009
        },
        {
          "period_end": "2028-12-31",
          "p_yes": 0.0011
        },
        {
          "period_end": "2029-03-31",
          "p_yes": 0.0013
        },
        {
          "period_end": "2029-06-30",
          "p_yes": 0.0015
        },
        {
          "period_end": "2029-09-30",
          "p_yes": 0.0017
        },
        {
          "period_end": "2029-12-31",
          "p_yes": 0.0019
        },
        {
          "period_end": "2030-03-31",
          "p_yes": 0.0021
        },
        {
          "period_end": "2030-06-30",
          "p_yes": 0.0024
        },
        {
          "period_end": "2030-09-30",
          "p_yes": 0.0026
        },
        {
          "period_end": "2030-12-31",
          "p_yes": 0.0029
        },
        {
          "period_end": "2031-03-31",
          "p_yes": 0.0032
        },
        {
          "period_end": "2031-06-30",
          "p_yes": 0.0035
        },
        {
          "period_end": "2031-09-30",
          "p_yes": 0.0038
        },
        {
          "period_end": "2031-12-31",
          "p_yes": 0.0041
        }
      ],
      "passes": []
    },
    {
      "question_id": "W223",
      "forecast_date": "2026-10-10",
      "evidence_cutoff": "2026-10-10",
      "method": "wide-v2.1",
      "opened": "2026-09-16",
      "linked_questions": [],
      "reading_adopted": null,
      "summary": "All eight consumer price groups are at or near record highs. Prices are rising about 3.4% a year and the Federal Reserve is raising interest rates. Halving any group would take about 13% price falls every year for five years. Since 1947 the worst five-year fall in any group is about 11%, and only clothing in 1920–1933 ever fell by half. The development that would most change this forecast is a sustained, unprecedented fall in prices across a whole group.",
      "ambiguities": [],
      "key_drivers": [],
      "would_update_on": [],
      "forecasts": [
        {
          "period_end": "2026-12-31",
          "p_yes": 0.0001
        },
        {
          "period_end": "2027-03-31",
          "p_yes": 0.0002
        },
        {
          "period_end": "2027-06-30",
          "p_yes": 0.0003
        },
        {
          "period_end": "2027-09-30",
          "p_yes": 0.0004
        },
        {
          "period_end": "2027-12-31",
          "p_yes": 0.0005
        },
        {
          "period_end": "2028-03-31",
          "p_yes": 0.0007
        },
        {
          "period_end": "2028-06-30",
          "p_yes": 0.0008
        },
        {
          "period_end": "2028-09-30",
          "p_yes": 0.001
        },
        {
          "period_end": "2028-12-31",
          "p_yes": 0.0011
        },
        {
          "period_end": "2029-03-31",
          "p_yes": 0.0013
        },
        {
          "period_end": "2029-06-30",
          "p_yes": 0.0015
        },
        {
          "period_end": "2029-09-30",
          "p_yes": 0.0017
        },
        {
          "period_end": "2029-12-31",
          "p_yes": 0.0019
        },
        {
          "period_end": "2030-03-31",
          "p_yes": 0.0022
        },
        {
          "period_end": "2030-06-30",
          "p_yes": 0.0024
        },
        {
          "period_end": "2030-09-30",
          "p_yes": 0.0027
        },
        {
          "period_end": "2030-12-31",
          "p_yes": 0.0029
        },
        {
          "period_end": "2031-03-31",
          "p_yes": 0.0032
        },
        {
          "period_end": "2031-06-30",
          "p_yes": 0.0035
        },
        {
          "period_end": "2031-09-30",
          "p_yes": 0.0038
        },
        {
          "period_end": "2031-12-31",
          "p_yes": 0.0041
        }
      ],
      "passes": []
    },
    {
      "question_id": "W223",
      "forecast_date": "2026-10-17",
      "evidence_cutoff": "2026-10-17",
      "method": "wide-v2.1",
      "opened": "2026-09-16",
      "linked_questions": [],
      "reading_adopted": null,
      "summary": "This is very unlikely. All eight consumer price groups are at or within 1% of record highs, inflation is 3.7% and the Federal Reserve is raising rates. No group has ever lost half its value within five years. Since 1950 the largest drop was 23%, in transportation costs in 2008. What would most change this forecast is the start of a sustained, deep general fall in prices, for example from an extreme economic shock driven by AI.",
      "ambiguities": [],
      "key_drivers": [],
      "would_update_on": [],
      "forecasts": [
        {
          "period_end": "2026-12-31",
          "p_yes": 0.00001
        },
        {
          "period_end": "2027-03-31",
          "p_yes": 0.00002
        },
        {
          "period_end": "2027-06-30",
          "p_yes": 0.00003
        },
        {
          "period_end": "2027-09-30",
          "p_yes": 0.00005
        },
        {
          "period_end": "2027-12-31",
          "p_yes": 0.00008
        },
        {
          "period_end": "2028-03-31",
          "p_yes": 0.00013
        },
        {
          "period_end": "2028-06-30",
          "p_yes": 0.00019
        },
        {
          "period_end": "2028-09-30",
          "p_yes": 0.00026
        },
        {
          "period_end": "2028-12-31",
          "p_yes": 0.00034
        },
        {
          "period_end": "2029-03-31",
          "p_yes": 0.00044
        },
        {
          "period_end": "2029-06-30",
          "p_yes": 0.00055
        },
        {
          "period_end": "2029-09-30",
          "p_yes": 0.00067
        },
        {
          "period_end": "2029-12-31",
          "p_yes": 0.0008
        },
        {
          "period_end": "2030-03-31",
          "p_yes": 0.00095
        },
        {
          "period_end": "2030-06-30",
          "p_yes": 0.00111
        },
        {
          "period_end": "2030-09-30",
          "p_yes": 0.00128
        },
        {
          "period_end": "2030-12-31",
          "p_yes": 0.00146
        },
        {
          "period_end": "2031-03-31",
          "p_yes": 0.00166
        },
        {
          "period_end": "2031-06-30",
          "p_yes": 0.00187
        },
        {
          "period_end": "2031-09-30",
          "p_yes": 0.00209
        },
        {
          "period_end": "2031-12-31",
          "p_yes": 0.00232
        }
      ],
      "passes": []
    }
  ],
  "declined": []
}