IESET.
Hypotheses·labour·labour_reform_japan_dispatch_worker_2004_duality

Japan's 2004 Worker Dispatch Law amendment (manufacturing- sector liberalisation effective 2004-Q1, period extension to 3 years) raised the Japanese non-regular-worker share by at least 4 pp by 2008 relative to a synthetic control of high-income peers, but did not raise aggregate employment rate above donor pool baseline.

PARTIALengine/runs/labour_reform_japan_dispatch_worker_2004_duality

PARTIAL — mean_gap=-0.777, |gap|/pre_sd=0.9, p_perm=0.857 (gap below 0.5×pre_sd or placebo p≥0.10)

confidence cueThe result is useful, but not decisive. Treat it as a clue, not a settled conclusion.

policy briefMixed or noisy

In ordinary language

Over a long period, do more market-oriented institutions translate into higher income or productivity, once the comparison looks beyond a single success story?

plain answer

The evidence is suggestive but not decisive. mean_gap=-0.777, |gap|/pre_sd=0.9, p_perm=0.857 (gap below 0.5×pre_sd or placebo p≥0.10)

why it matters

Labor-market rules often help some workers while risking job loss or slower hiring for others. This test looks for that tradeoff in observable employment or unemployment data.

how the test works

It compares 8 country or place units from 1995 to 2010, using a synth did design, with fixed effects for country and year.

what was measured
What changed
  • Japan dispatch 2004 amendment
What we checked
  • Non regular worker share
  • Employment to population ratio
  • Unemployment 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/labour_reform_japan_dispatch_worker_2004_duality
1007550250199520032010JPNKORTWNUSAGBRDEUFRA
illustrative sketch · run pending
No coefficients yet. When the model fires, this chart will show non_regular_worker_share across 8 sampled countries over 1995–2010.
The shapes above are stylised — none of the lines are real data.
Placeholder for labour_reform_japan_dispatch_worker_2004_duality. Published chart will be generated from engine/runs/labour_reform_japan_dispatch_worker_2004_duality/chart_data.json.

Pre-registration

pre-registered
first-spec commit 098ce96 · 2026-04-30T12:57:33Z
run generated · 2026-04-30T10:15:30Z

Japan's 2004 Worker Dispatch Law amendment (manufacturing- sector liberalisation effective 2004-Q1, period extension to 3 years) raised the Japanese non-regular-worker share by at least 4 pp by 2008 relative to a synthetic control of high-income peers, but did not raise aggregate employment rate above donor pool baseline.

Falsification criterion — what would disprove this

set before the run · honoured after

This hypothesis is considered falsified if:

SUPPORTED if synth-DiD gap on Japanese non-regular-worker share > +4 pp by 2008 AND aggregate-employment-rate gap is statistically indistinguishable from zero. REFUTED if duality gap < +2 pp OR aggregate employment gap is significantly positive at p<0.10 (employment-bonus story dominates duality story).

formal test & threshold
test:      Synth-DiD on Japanese non-regular-worker share and employment rate 2004-2008 vs high-income donor pool, placebo permutation at p<0.10.

Method

Template
synth_did
Fixed effects
country, year
Clustering
country
Sample
8 countries · 1995 – 2010
Evidence type
associational

Data

VariableSourceTransform
non_regular_worker_share
outcome
oecd:DSD_LFStier 2
level
employment_to_population_ratio
outcome
world_bank_wdi:SL.EMP.TOTL.SP.ZStier 2
level
unemployment_rate
outcome
world_bank_wdi:SL.UEM.TOTL.ZStier 2
level
japan_dispatch_2004_amendment
treatment
constructed:indicator for 2004-Q1 manufacturing dispatch liberalisationtier 5
indicator
gdp_per_capita_real
control
world_bank_wdi:NY.GDP.PCAP.KDtier 2
log
trade_openness
control
world_bank_wdi:NE.TRD.GNFS.ZStier 2
level
working_age_population_share
control
world_bank_wdi:SP.POP.1564.TO.ZStier 2
level

● ready  · ● pending  · ● reconstruct-needed

Detailed result card

Result card — labour_reform_japan_dispatch_worker_2004_duality

Verdict: PARTIAL — mean_gap=-0.777, |gap|/pre_sd=0.9, p_perm=0.857 (gap below 0.5×pre_sd or placebo p≥0.10)

Pre-registration

  • Claim: Japan's 2004 Worker Dispatch Law amendment (manufacturing- sector liberalisation effective 2004-Q1, period extension to 3 years) raised the Japanese non-regular-worker share by at least 4 pp by 2008 relative to a synthetic control of high-income peers, but did not raise aggregate employment rate above donor pool baseline.
  • Falsification rule: SUPPORTED if synth-DiD gap on Japanese non-regular-worker share > +4 pp by 2008 AND aggregate-employment-rate gap is statistically indistinguishable from zero. REFUTED if duality gap < +2 pp OR aggregate employment gap is significantly positive at p<0.10 (employment-bonus story dominates duality story).

Synthetic-control estimate

  • shape: synth_did
  • treated_country: JPN
  • event_year: 2004
  • n_donors: 6
  • donor_weights (top): {'USA': 0.6473, 'KOR': 0.3527, 'GBR': 0.0, 'DEU': 0.0, 'FRA': 0.0}
  • pre_rmse: 0.815147981266938
  • pre_period_sd: 0.8660408156919882
  • mean_post_gap: -0.7770405588400129
  • end_period_gap: -2.306051542785829
  • post_period_years: [2004, 2010]
  • placebo_p_value: 0.8571428571428571
  • n_placebos: 6
  • method: synthetic-control via NNLS, permutation inference

Variables resolved

  • world_bank_wdi:SL.UEM.TOTL.ZS → unemployment_rate (outcome, n=8106)
  • world_bank_wdi:NY.GDP.PCAP.KD → gdp_per_capita_real (controls, n=14131)
  • world_bank_wdi:NE.TRD.GNFS.ZS → trade_openness (controls, n=10779)

Generated by scripts/run_synth_did.py at 2026-04-30T10:15:30+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

Treatment dated 2004-Q1 (manufacturing dispatch ban lifted). Japanese case is structurally important because dispatch- worker liberalisation is widely credited with the post-2008 Japan-specific labour-market vulnerability that surfaced in the GFC. The hypothesis is symmetric on the aggregate- employment margin.

Authored framework. Read the transparency note.