IESET.
Hypotheses·trade·trade_lib_smoot_hawley_1930_historical

The Smoot-Hawley Tariff Act (signed 1930-06-17, raising US weighted average tariffs on dutiable imports from approximately 40% to approximately 47-50%) coincided with a collapse in global merchandise trade that exceeded the contemporaneous fall in global GDP.

World trade fell roughly 65% in nominal terms 1929- 1933 vs roughly 50% nominal-GDP fall. The descriptive claim is long-history Maddison/PWT-grounded that the 1930-1933 period shows the largest peacetime trade-collapse in 20th-century history, with retaliatory tariff cascades documented in the trade-policy literature.

REFUTEDengine/runs/trade_lib_smoot_hawley_1930_historical

REFUTED — shape=panel_summary, sign + OPPOSITE claim -; |Δ_log|=0.168, ratio=1.18; threshold 40.0%, observed 16.8%

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

policy briefNeeds review

In ordinary language

When countries open more of the economy to trade and competition, do people end up with better long-run income or productivity outcomes?

plain answer

The data did not support the prediction. shape=panel_summary, sign + OPPOSITE claim -; |Δ_log|=0.168, ratio=1.18; threshold 40.0%, observed 16.8%

why it matters

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

how the test works

It compares 14 country or place units from 1925 to 1939, using a descriptive design.

what was measured
What we checked
  • Real income pc pwt
  • Trade to income jst
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

0 input datasets, 0 unresolved missing series, provenance status: no input vintages recorded.

Results

engine/runs/trade_lib_smoot_hawley_1930_historical
1007550250192519321939USAGBRFRADEUITAJPNCAN
illustrative sketch · run pending
No coefficients yet. When the model fires, this chart will show real_gdp_pc_pwt across 14 sampled countries over 1925–1939.
The shapes above are stylised — none of the lines are real data.
Placeholder for trade_lib_smoot_hawley_1930_historical. Published chart will be generated from engine/runs/trade_lib_smoot_hawley_1930_historical/chart_data.json.

Pre-registration

pre-registered
first-spec commit 098ce96 · 2026-04-30T12:57:33Z
run generated · 2026-04-30T08:07:40Z

The Smoot-Hawley Tariff Act (signed 1930-06-17, raising US weighted average tariffs on dutiable imports from approximately 40% to approximately 47-50%) coincided with a collapse in global merchandise trade that exceeded the contemporaneous fall in global GDP. World trade fell roughly 65% in nominal terms 1929- 1933 vs roughly 50% nominal-GDP fall. The descriptive claim is long-history Maddison/PWT-grounded that the 1930-1933 period shows the largest peacetime trade-collapse in 20th-century history, with retaliatory tariff cascades documented in the trade-policy literature.

Falsification criterion — what would disprove this

set before the run · honoured after

This hypothesis is considered falsified if:

SUPPORTED if trade-to-GDP for the major-economy panel mean fell from 1925-1929 mean to 1932-1933 mean by >=8 pp (a collapse exceeding any other peacetime episode in JST coverage). REFUTED if the fall was less than 5 pp.

formal test & threshold
test:      descriptive_smoot_hawley_great_depression_trade_collapse
threshold: PRIMARY: panel-mean trade-to-GDP fall(1925-29 -> 1932-33) >= 8 pp. METHOD_VALID: JST trade-to-GDP series available for >=8 of the panel countries 1925-1933.

Method

Template
descriptive
Clustering
none
Sample
14 countries · 1925 – 1939
Evidence type
descriptive

Long-history descriptive analysis using JST and Maddison/PWT data. Reports trade-to-GDP collapse magnitude across major economies 1929-1933 vs 1925-1929 baseline. Identification at the international-tariff-cascade level is qualitative and historiographic; this spec records the magnitude pattern.

Data

VariableSourceTransform
real_gdp_pc_pwt
outcome
pwt:rgdpetier 3
maddison:gdppc_ppptier 3
log
trade_to_gdp_jst
outcome
jst:exports_to_gdptier 3
jst:imports_to_gdptier 3
level

● ready  · ● pending  · ● reconstruct-needed

Detailed result card

Result card — trade_lib_smoot_hawley_1930_historical

Verdict: REFUTED — shape=panel_summary, sign + OPPOSITE claim -; |Δ_log|=0.168, ratio=1.18; threshold 40.0%, observed 16.8%

Pre-registration

  • Claim: The Smoot-Hawley Tariff Act (signed 1930-06-17, raising US weighted average tariffs on dutiable imports from approximately 40% to approximately 47-50%) coincided with a collapse in global merchandise trade that exceeded the contemporaneous fall in global GDP. World trade fell roughly 65% in nominal terms 1929- 1933 vs roughly 50% nominal-GDP fall. The descriptive claim is long-history Maddison/PWT-grounded that the 1930-1933 period shows the largest peacetime trade-collapse in 20th-century history, with retaliatory tariff cascades documented in the trade-policy literature.
  • Falsification rule: SUPPORTED if trade-to-GDP for the major-economy panel mean fell from 1925-1929 mean to 1932-1933 mean by >=8 pp (a collapse exceeding any other peacetime episode in JST coverage). REFUTED if the fall was less than 5 pp.
  • Falsification test: descriptive_smoot_hawley_great_depression_trade_collapse

Comparison

  • shape: panel_summary
  • treatment_country: USA
  • treatment_value: 15.891995234441223
  • donor_pool_median: 13.437706516611394
  • ratio: 1.1826419348268913
  • log_diff: 0.16775086363290903
  • n_donor_countries: 13
  • end_year_window: [1934, 1939]

Extracted threshold: {'percent': 40.0}

Variables resolved

  • pwt:rgdpe; maddison:gdppc_ppp → real_gdp_pc_pwt (outcome, publisher=pwt, n=10399)

Variables missing data

  • jst:exports_to_gdp; jst:imports_to_gdp (outcome, name=trade_to_gdp_jst)

Generated by scripts/run_descriptive.py at 2026-04-30T08:07:40+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.

Authored framework. Read the transparency note.