IESET.
Hypotheses·monetary·japan_public_debt_solvency_inflation_independence

Japanese public debt crossing 150%, then 200%, then 250% of GDP 1990-2020 did not trigger a solvency or inflation crisis, contradicting household-debt-analogue framings.

WEAKENEDengine/runs/japan_public_debt_solvency_inflation_independence

WEAKENED — observed crossed thresholds clear the 300bp-yield and 5% CPI gates; local IMF debt vintage does not cross 250%

confidence cueThis test cuts against the claim as written or misses its pre-declared threshold.

policy briefNeeds review

In ordinary language

In plain terms, this asks whether gross public debt pct income is actually linked to better or worse jgb yield 10y from 1990 to 2020.

plain answer

observed crossed thresholds clear the 300bp-yield and 5% CPI gates; local IMF debt vintage does not cross 250%

why it matters

This matters because monetary claims should change belief only when they survive a pre-declared empirical test.

how the test works

It compares 1 country or place units from 1990 to 2020, using a descriptive design.

what was measured
What changed
  • Gross public debt pct income
  • Boj jgb holdings pct outstanding
What we checked
  • Jgb yield 10y
  • Cpi inflation
  • Jpy usd exchange rate
what this does not prove

A single test is not the whole truth. It narrows the claim under a specific sample, time period, and method. Strong policy conclusions need the pattern to survive nearby tests, alternative data, and serious objections.

verification

No evidence packet has been generated yet.

Results

engine/runs/japan_public_debt_solvency_inflation_independence
1007550250199020052020JPN
illustrative sketch · run pending
No coefficients yet. When the model fires, this chart will show jgb_yield_10y across 1 sampled countries over 1990–2020.
The shapes above are stylised — none of the lines are real data.
Placeholder for japan_public_debt_solvency_inflation_independence. Published chart will be generated from engine/runs/japan_public_debt_solvency_inflation_independence/chart_data.json.

Who has skin in the game — schools predicting on this

1 school list this hypothesis as a test of their position. The chips below are school-level scoreboard outcomes, not a second hypothesis verdict.

hypothesis verdict vs scoreboard outcome

The banner verdict judges this hypothesis as written. The scoreboard asks whether each school's polarity-corrected prediction was right. Raw status is not a school win: SUPPORTED supports schools that needed SUPPORTED, but refutes schools that needed REFUTED.

Modern Monetary Theorywins if SUPPORTEDpartial/no-call

Pre-registration

pre-registered
first-spec commit bae09ab · 2026-04-29T22:09:42Z
run generated · 2026-05-16T13:19:41Z

Japanese public debt crossing 150%, then 200%, then 250% of GDP 1990-2020 did not trigger a solvency or inflation crisis, contradicting household-debt-analogue framings.

Falsification criterion — what would disprove this

set before the run · honoured after

This hypothesis is considered falsified if:

SUPPORTED if Japan crosses the 150%, 200%, and 250% gross-public-debt/GDP thresholds without either (a) a 10y JGB yield spike of more than 300 basis points above the trailing-12-month pre-threshold mean within the following 24 months, or (b) CPI inflation above 5% year-over-year for at least 12 consecutive months within the following 24 months. REFUTED if any debt threshold crossing is followed by either crisis condition. WEAKENED if one primary series is missing at a threshold but the observed series does not breach. METHOD_VALID requires the IMF debt/GDP, FRED 10y JGB yield, and FRED CPI series to cover the threshold windows between 1990 and 2020.

formal test & threshold
test:      Descriptive multi-metric pattern check: JPN debt/GDP, 10y JGB yield, CPI, BoJ holdings 1990-2020; no >300bp yield spike or >5% sustained inflation at 150/200/250% thresholds supports the claim.

Method

Template
descriptive
Clustering
episode
Sample
1 countries · 1990 – 2020
Evidence type
associational

Stub-level estimator pin for runnability audit. Descriptive trajectory of Japanese gross public debt / GDP, 10y JGB yield, CPI inflation, and BoJ holdings 1990-2020. Pattern-test: no breach of household-debt-style solvency triggers (yield spike, inflation spike, downgrade-driven exit of marginal investors) across 150% / 200% / 250% debt thresholds. Falsification rule and variables block remain to be filled when this stub is promoted from draft.

Data

VariableSourceTransform
jgb_yield_10y
outcome
boj:bond_yields_10ytier 1
fred:IRLTLT01JPM156Ntier 1
level
cpi_inflation
outcome
boj:CPItier 1
fred:JPNCPIALLMINMEItier 1
pct_change_yoy
jpy_usd_exchange_rate
outcome
fred:DEXJPUStier 1
bis:WS_EERtier 2
log_level
gross_public_debt_pct_gdp
treatment
imf:GGXWDG_NGDPtier 2
world_bank_wdi:GC.DOD.TOTL.GD.ZStier 2
level_pct
boj_jgb_holdings_pct_outstanding
treatment
boj:money_stock_m2tier 1
level_pct
real_gdp_growth
control
world_bank_wdi:NY.GDP.MKTP.KD.ZGtier 2
pct_change_yoy
current_account_pct_gdp
control
imf:BCA_NGDPDtier 2
level
sovereign_cds_5y
control
academic:bloomberg_cdstier 4
level

● ready  · ● pending  · ● reconstruct-needed

Detailed result card

Result card — japan_public_debt_solvency_inflation_independence

Verdict: WEAKENED — observed crossed thresholds clear the 300bp-yield and 5% CPI gates; local IMF debt vintage does not cross 250%

Pre-registration

  • Claim: Japanese public debt crossing 150%, then 200%, then 250% of GDP 1990-2020 did not trigger a solvency or inflation crisis, contradicting household-debt-analogue framings.
  • Falsification rule: SUPPORTED if Japan crosses the 150%, 200%, and 250% gross-public-debt/GDP thresholds without either (a) a 10y JGB yield spike of more than 300 basis points above the trailing-12-month pre-threshold mean within the following 24 months, or (b) CPI inflation above 5% year-over-year for at least 12 consecutive months within the following 24 months. REFUTED if any debt threshold crossing is followed by either crisis condition. WEAKENED if one primary series is missing at a threshold but the observed series does not breach. METHOD_VALID requires the IMF debt/GDP, FRED 10y JGB yield, and FRED CPI series to cover the threshold windows between 1990 and 2020.
  • Falsification test: Descriptive multi-metric pattern check: JPN debt/GDP, 10y JGB yield, CPI, BoJ holdings 1990-2020; no >300bp yield spike or >5% sustained inflation at 150/200/250% thresholds supports the claim.

Comparison

  • shape: japan_debt_threshold_gate
  • country: JPN
  • period: [1990, 2020]
  • threshold_rows: [{'threshold_debt_pct_gdp': 150.0, 'status': 'crossed', 'cross_year': 2005, 'debt_pct_gdp_at_cross': 153.4, 'pre_cross_yield': {'year': 2004, 'value': 1.4926666666666666}, 'max_10y_yield_next_2y': 1.7405, 'yield_spike_pp_next_2y': 0.24783333333333335, 'max_cpi_yoy_next_2y': 0.2538075233387893, 'yield_spike_breach_gt_3pp': False, 'cpi_breach_gt_5pct': False}, {'threshold_debt_pct_gdp': 200.0, 'status': 'crossed', 'cross_year': 2013, 'debt_pct_gdp_at_cross': 201.2, 'pre_cross_yield': {'year': 2012, 'value': 0.8355833333333332}, 'max_10y_yield_next_2y': 0.6896666666666667, 'yield_spike_pp_next_2y': -0.14591666666666658, 'max_cpi_yoy_next_2y': 2.7592334693625986, 'yield_spike_breach_gt_3pp': False, 'cpi_breach_gt_5pct': False}, {'threshold_debt_pct_gdp': 250.0, 'status': 'not_crossed_in_local_vintage', 'max_local_debt_pct_gdp': 228.8}]
  • post_first_debt_crossing_gate: {}
  • debt_yield_regression: None
  • distress_event_count: None
  • distress_event_count_source: None
  • data_coverage: {'debt_years': [1980, 2031], 'jgb_years': [1989, 2026], 'cpi_years': [1955, 2021]}

Extracted threshold: {'percent': 150.0}

Variables resolved

  • boj:bond_yields_10y; fred:IRLTLT01JPM156N → jgb_yield_10y (outcome, publisher=fred, n=38)
  • boj:CPI; fred:JPNCPIALLMINMEI → cpi_inflation (outcome, publisher=fred, n=67)
  • fred:DEXJPUS; bis:WS_EER → jpy_usd_exchange_rate (outcome, publisher=fred, n=56)
  • imf:GGXWDG_NGDP; world_bank_wdi:GC.DOD.TOTL.GD.ZS → gross_public_debt_pct_gdp (treatment, publisher=imf, n=8113)
  • world_bank_wdi:NY.GDP.MKTP.KD.ZG → real_gdp_growth (controls, publisher=world_bank_wdi, n=13897)
  • imf:BCA_NGDPD → current_account_pct_gdp (controls, publisher=imf, n=10556)

Variables missing data

  • boj:money_stock_m2 (treatment, name=boj_jgb_holdings_pct_outstanding)
  • academic:bloomberg_cds (controls, name=sovereign_cds_5y)

Generated by scripts/run_descriptive.py at 2026-05-16T13:19:41+00:00

Strongest opposing argument

Every hypothesis ships with its charitable opposing argument. The framework earns credibility by handling objections at their strongest, not weakest.

Notes

Promoted from coverage-gap stub on 2026-05-03. v1 uses a descriptive threshold test around Japan's 150/200/250 percent gross-public-debt/GDP crossings, with FRED 10y JGB yield, FRED CPI, FRED JPY/USD, IMF gross debt/GDP, IMF current-account balance, and WDI real-GDP growth. BoJ JGB-holdings share remains an informative missing series, not a primary gate.

Authored framework. Read the transparency note.