IESET.
Hypotheses·distribution·tax_inequality_france_2017_isf_to_ifi_abolition

Macron's 2017 reform replacing the French ISF (Impot de Solidarite sur la Fortune) with the IFI (real-estate-only wealth tax) and the introduction of the 30 percent flat tax (PFU) on capital income produced a measurable rise in the French top-1 pre-tax income share over 2018-2022 relative to Eurozone synthetic control, but a smaller-than-projected fall in HNW emigration once concurrent CRS enforcement is accounted for.

The discriminating test pairs top-share rise vs HNW outbound migration vs synthetic-control trajectory.

PARTIALengine/runs/tax_inequality_france_2017_isf_to_ifi_abolition

PARTIAL — mean_gap=+1.331, |gap|/pre_sd=2.2, p_perm=1 (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=+1.331, |gap|/pre_sd=2.2, p_perm=1 (gap below 0.5×pre_sd or placebo p≥0.10)

why it matters

Distributional claims often sound morally clear but are empirically complex. This test asks whether the proposed channel explains real differences across places.

how the test works

It compares 9 country or place units from 2010 to 2023, using a synthetic control design, with fixed effects for country and year.

what was measured
What changed
  • Isf to ifi 2018 fra post
  • Top marginal income tax rate
What we checked
  • Top 1pct pretax income share
  • Top 1pct wealth share
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/tax_inequality_france_2017_isf_to_ifi_abolition
1007550250201020172023FRADEUITAESPNLDBELAUT
illustrative sketch · run pending
No coefficients yet. When the model fires, this chart will show top_1pct_pretax_income_share across 9 sampled countries over 2010–2023.
The shapes above are stylised — none of the lines are real data.
Placeholder for tax_inequality_france_2017_isf_to_ifi_abolition. Published chart will be generated from engine/runs/tax_inequality_france_2017_isf_to_ifi_abolition/chart_data.json.

Who has skin in the game — schools predicting on this

9 schools 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.

Degrowth / Ecological Macroeconomicswins if SUPPORTEDpartial/no-callDemocratic Socialism (Bernsteinian revisionism + modern)wins if SUPPORTEDpartial/no-callEco-Socialism / Red-Greenwins if SUPPORTEDpartial/no-callMarket Socialism (Lange-Lerner tradition)wins if SUPPORTEDpartial/no-callMarxian Political Economywins if SUPPORTEDpartial/no-callMarxism-Leninism (central-planning implementation)wins if SUPPORTEDpartial/no-callModern Monetary Theorywins if SUPPORTEDpartial/no-callNew Keynesian (mainstream synthesis)wins if SUPPORTEDpartial/no-callPost-Keynesianwins if SUPPORTEDpartial/no-call

Pre-registration

registration ordering unverified
first-spec commit 4c8ce8e · 2026-07-18T22:11:21Z
run generated · 2026-05-04T08:09:56Z
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.

Macron's 2017 reform replacing the French ISF (Impot de Solidarite sur la Fortune) with the IFI (real-estate-only wealth tax) and the introduction of the 30 percent flat tax (PFU) on capital income produced a measurable rise in the French top-1 pre-tax income share over 2018-2022 relative to Eurozone synthetic control, but a smaller-than-projected fall in HNW emigration once concurrent CRS enforcement is accounted for. The discriminating test pairs top-share rise vs HNW outbound migration vs synthetic-control trajectory.

Falsification criterion — what would disprove this

set before the run · honoured after

This hypothesis is considered falsified if:

SUPPORTED if French top-1 pretax share rises by at least 0.75 percentage points 2017-2022 vs synthetic-control trajectory at p<0.10. REFUTED if no detectable gap (within 0.3pp) or the gap is negative at five-year horizon.

formal test & threshold
test:      Synthetic-control with Eurozone donor pool, treated FRA 2018.

Method

Template
synthetic_control
Fixed effects
country, year
Clustering
country
Sample
9 countries · 2010 – 2023
Evidence type
associational

Synthetic-control with Eurozone donor pool. Treated FRA 2018. Placebo- in-time at 2014. Robustness with synth_did.

Data

VariableSourceTransform
top_1pct_pretax_income_share
outcome
owid:top-1-share-of-total-incometier 2
level
top_1pct_wealth_share
outcome
owid:top-1-share-of-total-wealthtier 2
level
isf_to_ifi_2018_fra_post
treatment
constructed:indicator = 1 for FRA, year >= 2018tier 5
indicator
top_marginal_income_tax_rate
treatment
owid:top-marginal-income-tax-ratetier 2
level
log_real_gdp_per_capita
control
world_bank_wdi:NY.GDP.PCAP.KDtier 2
log
trade_openness
control
world_bank_wdi:NE.TRD.GNFS.ZStier 2
level

● ready  · ● pending  · ● reconstruct-needed

Detailed result card

Result card — tax_inequality_france_2017_isf_to_ifi_abolition

Verdict: PARTIAL — mean_gap=+1.331, |gap|/pre_sd=2.2, p_perm=1 (gap below 0.5×pre_sd or placebo p≥0.10)

Pre-registration

  • Claim: Macron's 2017 reform replacing the French ISF (Impot de Solidarite sur la Fortune) with the IFI (real-estate-only wealth tax) and the introduction of the 30 percent flat tax (PFU) on capital income produced a measurable rise in the French top-1 pre-tax income share over 2018-2022 relative to Eurozone synthetic control, but a smaller-than-projected fall in HNW emigration once concurrent CRS enforcement is accounted for. The discriminating test pairs top-share rise vs HNW outbound migration vs synthetic-control trajectory.
  • Falsification rule: SUPPORTED if French top-1 pretax share rises by at least 0.75 percentage points 2017-2022 vs synthetic-control trajectory at p<0.10. REFUTED if no detectable gap (within 0.3pp) or the gap is negative at five-year horizon.

Synthetic-control estimate

  • shape: synth_did
  • treated_country: FRA
  • event_year: 2017
  • n_donors: 3
  • donor_weights (top): {'FIN': 0.8951, 'PRT': 0.1049, 'DEU': 0.0}
  • pre_rmse: 1.1035329228493052
  • pre_period_sd: 0.6064023495368479
  • mean_post_gap: 1.3307152102550885
  • end_period_gap: 2.088055498089437
  • post_period_years: [2017, 2022]
  • placebo_p_value: 1.0
  • n_placebos: 3
  • method: synthetic-control via NNLS, permutation inference

Variables resolved

  • owid:top-1-share-of-total-income → top_1pct_pretax_income_share (outcome, n=3294)
  • owid:top-1-share-of-total-wealth → top_1pct_wealth_share (outcome, n=10811)
  • constructed: indicator = 1 for FRA, year >= 2018 → isf_to_ifi_2018_fra_post (treatment, n=126)
  • owid:top-marginal-income-tax-rate → top_marginal_income_tax_rate (treatment, n=590)
  • world_bank_wdi:NY.GDP.PCAP.KD → log_real_gdp_per_capita (controls, n=14066)
  • world_bank_wdi:NE.TRD.GNFS.ZS → trade_openness (controls, n=10714)

Generated by scripts/run_synth_did.py at 2026-05-04T08:09:56+00:00

Notes

Tax-inequality candidate, swarm-S6 batch 2. Tests the "ISF abolition caused exodus reversal" narrative against the broader CRS-enforcement confound.

Authored framework. Read the transparency note.