IESET.
Hypotheses·labour·demo_uk_post_2004_eu_migration

The UK's decision not to apply transitional restrictions on A8 (2004) accession-state migration produced a large inflow (~1.5 million by 2014), particularly Polish-origin.

The hypothesis tests (a) the magnitude of the working-age population contribution from A8 migration, and (b) whether wage effects in low-wage sectors detectable in pre-Brexit UK panel data are small (consistent with Wadsworth-Dustmann findings) or substantial.

PARTIALengine/runs/demo_uk_post_2004_eu_migration

PARTIAL — shape=ITS, mean_gap=-0.191, z=-8.4; claim direction ambiguous

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

policy briefMixed or noisy

In ordinary language

In plain terms, this asks whether a8 accession indicator is actually linked to better or worse real wage low decile from 1995 to 2020.

plain answer

The evidence is suggestive but not decisive. shape=ITS, mean_gap=-0.191, z=-8.4; claim direction ambiguous

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 1 country or place units from 1995 to 2020, using a event study design.

what was measured
What changed
  • A8 accession indicator
What we checked
  • Real wage low decile
  • Foreign born share population
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/demo_uk_post_2004_eu_migration
1007550250199520082020GBR
illustrative sketch · run pending
No coefficients yet. When the model fires, this chart will show real_wage_low_decile across 1 sampled countries over 1995–2020.
The shapes above are stylised — none of the lines are real data.
Placeholder for demo_uk_post_2004_eu_migration. Published chart will be generated from engine/runs/demo_uk_post_2004_eu_migration/chart_data.json.

Pre-registration

registration ordering unverified
first-spec commit 4c8ce8e · 2026-07-18T22:11:21Z
run generated · 2026-05-01T07:18:51Z
Run timestamp predates this path's first git-add commit (rebase, rename, or pre-git local run). Spec hash is still the path's first-add commit — not repository HEAD — but ordering is not a clean pre-registration proof.

The UK's decision not to apply transitional restrictions on A8 (2004) accession-state migration produced a large inflow (~1.5 million by 2014), particularly Polish-origin. The hypothesis tests (a) the magnitude of the working-age population contribution from A8 migration, and (b) whether wage effects in low-wage sectors detectable in pre-Brexit UK panel data are small (consistent with Wadsworth-Dustmann findings) or substantial.

Falsification criterion — what would disprove this

set before the run · honoured after

This hypothesis is considered falsified if:

SUPPORTED if foreign-born share trajectory shows structural break at 2004 with post-break slope at least 2x pre-break slope, AND bottom-decile real wage growth shows small (< 0.5pp/yr negative) deviation from pre-trend over 2004-2014. REFUTED if no foreign-born break OR if low-wage growth deviation exceeds 1.5pp/yr negative.

formal test & threshold
test:      event_study_uk_a8_2004_with_low_wage_response
threshold: fb_break_test_p < 0.05 AND fb_post_slope_ratio >= 2.0 AND low_wage_deviation > -1.5

Method

Template
event_study
Sample
1 countries · 1995 – 2020
Evidence type
associational

Single-country event study; pre-event 1995-2003, event 2004-2007 (transitional period), post-event 2007-2020. Report break in foreign-born trajectory and bottom-decile wage trajectory; benchmark wage break against pre-trend.

Data

VariableSourceTransform
real_wage_low_decile
outcome
oecd:OECD.ELS.SAEtier 2
log
foreign_born_share_population
outcome
un_desa:international_migrant_stocktier 2
level
a8_accession_indicator
treatment
constructed:indicator = 1 for years >= 2004tier 5
indicator
unemployment_rate
control
world_bank_wdi:SL.UEM.TOTL.ZStier 2
level
real_gdp_per_capita
control
world_bank_wdi:NY.GDP.PCAP.PP.KDtier 2
log

● ready  · ● pending  · ● reconstruct-needed

Detailed result card

Result card — demo_uk_post_2004_eu_migration

Verdict: PARTIAL — shape=ITS, mean_gap=-0.191, z=-8.4; claim direction ambiguous

Pre-registration

  • Claim: The UK's decision not to apply transitional restrictions on A8 (2004) accession-state migration produced a large inflow (~1.5 million by 2014), particularly Polish-origin. The hypothesis tests (a) the magnitude of the working-age population contribution from A8 migration, and (b) whether wage effects in low-wage sectors detectable in pre-Brexit UK panel data are small (consistent with Wadsworth-Dustmann findings) or substantial.
  • Falsification rule: SUPPORTED if foreign-born share trajectory shows structural break at 2004 with post-break slope at least 2x pre-break slope, AND bottom-decile real wage growth shows small (< 0.5pp/yr negative) deviation from pre-trend over 2004-2014. REFUTED if no foreign-born break OR if low-wage growth deviation exceeds 1.5pp/yr negative.
  • Falsification test: event_study_uk_a8_2004_with_low_wage_response
  • Event year: 2004

Estimate

  • shape: single_country_its
  • country: GBR
  • event_year: 2004
  • n_pre: 8
  • n_post: 17
  • pre_trend_slope: 0.01029722458822284
  • pre_trend_intercept: -17.3947490253488
  • pre_residual_sd: 0.022733433209898728
  • end_year: 2020
  • end_year_actual: 3.055358708108025
  • end_year_counterfactual: 3.4056446428613327
  • end_year_gap: -0.3502859347533076
  • mean_post_gap: -0.19104251691689314
  • z_end: -15.408404507981839
  • z_mean: -8.40359285608072
  • post_period_years: [2004, 2020]

Variables resolved

  • oecd:OECD.ELS.SAE,DSD_EARNINGS@DF_EARNINGS,1.0 → real_wage_low_decile (outcome, publisher=oecd, n=761)
  • un_desa:international_migrant_stock → foreign_born_share_population (outcome, publisher=un_desa, n=16)
  • constructed: indicator = 1 for years >= 2004 → a8_accession_indicator (treatment, publisher=constructed, n=26)
  • world_bank_wdi:SL.UEM.TOTL.ZS → unemployment_rate (controls, publisher=world_bank_wdi, n=8071)
  • world_bank_wdi:NY.GDP.PCAP.PP.KD → real_gdp_per_capita (controls, publisher=world_bank_wdi, n=8325)

Generated by scripts/run_event_study.py at 2026-05-01T07:18:51+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.