IESET.
Hypotheses·fiscal·africa_nigeria_fuel_subsidy_removal_2023

Nigeria's May 2023 elimination of the petrol subsidy under President Tinubu produced a fiscally favourable but socially costly trajectory: federally-retained revenue rose, the primary fiscal balance improved relative to the 2018-2022 baseline, but headline CPI inflation accelerated and household real-consumption proxies weakened in the 12-24 months post-removal.

The pre-registered claim is that, in a synthetic-control design with a Sub- Saharan African oil-exporter donor pool (Angola, Algeria, Gabon, Republic of Congo, Equatorial Guinea), Nigeria's primary fiscal balance share of GDP improves by at least 1.5 percentage points 2023-2025 vs synthetic counterfactual AND CPI inflation rises by at least 6 percentage points more than the synthetic counterfactual. The null counter-claim is that Nigeria's fiscal improvement is statistically indistinguishable from the donor-pool path once oil-price terms-of-trade and naira devaluation are netted out — i.e. the subsidy reform did not deliver fiscal repair distinct from windfall mechanics.

PARTIALengine/runs/africa_nigeria_fuel_subsidy_removal_2023

PARTIAL — mean_gap=+0.3137, |gap|/pre_sd=1.3, 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

In plain terms, this asks whether subsidy removal indicator is actually linked to better or worse primary fiscal balance share income from 2010 to 2025.

plain answer

The evidence is suggestive but not decisive. mean_gap=+0.3137, |gap|/pre_sd=1.3, p_perm=1 (gap below 0.5×pre_sd or placebo p≥0.10)

why it matters

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

how the test works

It compares 6 country or place units from 2010 to 2025, using a synth did design.

what was measured
What changed
  • Subsidy removal indicator
What we checked
  • Primary fiscal balance share income
  • Cpi inflation yoy
  • Real household consumption pc
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/africa_nigeria_fuel_subsidy_removal_2023
1007550250201020182025NGAAGODZAGABCOGGNQ
illustrative sketch · run pending
No coefficients yet. When the model fires, this chart will show primary_fiscal_balance_share_gdp across 6 sampled countries over 2010–2025.
The shapes above are stylised — none of the lines are real data.
Placeholder for africa_nigeria_fuel_subsidy_removal_2023. Published chart will be generated from engine/runs/africa_nigeria_fuel_subsidy_removal_2023/chart_data.json.

Pre-registration

registration ordering unverified
first-spec commit 4c8ce8e · 2026-07-18T22:11:21Z
run generated · 2026-04-30T10:15:29Z
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.

Nigeria's May 2023 elimination of the petrol subsidy under President Tinubu produced a fiscally favourable but socially costly trajectory: federally-retained revenue rose, the primary fiscal balance improved relative to the 2018-2022 baseline, but headline CPI inflation accelerated and household real-consumption proxies weakened in the 12-24 months post-removal. The pre-registered claim is that, in a synthetic-control design with a Sub- Saharan African oil-exporter donor pool (Angola, Algeria, Gabon, Republic of Congo, Equatorial Guinea), Nigeria's primary fiscal balance share of GDP improves by at least 1.5 percentage points 2023-2025 vs synthetic counterfactual AND CPI inflation rises by at least 6 percentage points more than the synthetic counterfactual. The null counter-claim is that Nigeria's fiscal improvement is statistically indistinguishable from the donor-pool path once oil-price terms-of-trade and naira devaluation are netted out — i.e. the subsidy reform did not deliver fiscal repair distinct from windfall mechanics.

Falsification criterion — what would disprove this

set before the run · honoured after

This hypothesis is considered falsified if:

Not supported if EITHER (a) synth_did CATT on primary_fiscal_balance over 2023Q3- 2025Q4 is less than +1.5 percentage points of GDP at p_perm < 0.10, OR (b) the inflation acceleration relative to synthetic counterfactual is less than +6 percentage points cumulative, OR (c) both the fiscal and inflation effects are inside the placebo distribution (indicating the reform did not produce a detectable break).

formal test & threshold
test:      synth_did_dual_outcome_with_permutation
threshold: CATT_2023Q3_2025Q4(primary_fiscal_balance_share_gdp) > 1.5 ppts at p_perm < 0.10 AND CATT(cpi_yoy) > 6 ppts cumulative at p_perm < 0.10

Method

Template
synth_did
Clustering
country
Sample
6 countries · 2010 – 2025
Evidence type
causal

Primary: synth_did with NGA treated from 2023Q3 and oil-exporter SSA + MENA donor pool. Secondary: Callaway-Sant'Anna DiD. Tertiary: local projections with quarters-since-removal interaction. Robustness includes excluding Angola (its own 2023 fiscal adjustment) and excluding 2024Q1 naira-redenomination noise.

Data

VariableSourceTransform
primary_fiscal_balance_share_gdp
outcome
world_bank_wdi:GC.NLD.TOTL.GD.ZStier 2
level
cpi_inflation_yoy
outcome
world_bank_wdi:FP.CPI.TOTL.ZGtier 2
imf:PCPIPCHtier 2
yoy
real_household_consumption_pc
outcome
world_bank_wdi:NE.CON.PRVT.PC.KDtier 2
log_level
fuel_pump_price
outcome
world_bank_wdi:EP.PMP.SGAS.CDtier 2
owid:fuel_pricestier 2
log_level
subsidy_removal_indicator
treatment
constructed:binary = 1 for NGA from 2023-06-01 onwardtier 5
binary
brent_oil_price
control
fred:DCOILBRENTEUtier 1
imf:POILBREtier 2
log_level
usd_exchange_rate_official
control
world_bank_wdi:PA.NUS.FCRFtier 2
log_level
terms_of_trade
control
world_bank_wdi:TT.PRI.MRCH.XD.WDtier 2
level
us_policy_rate
control
fred:FEDFUNDStier 1
level

● ready  · ● pending  · ● reconstruct-needed

Detailed result card

Result card — africa_nigeria_fuel_subsidy_removal_2023

Verdict: PARTIAL — mean_gap=+0.3137, |gap|/pre_sd=1.3, p_perm=1 (gap below 0.5×pre_sd or placebo p≥0.10)

Pre-registration

  • Claim: Nigeria's May 2023 elimination of the petrol subsidy under President Tinubu produced a fiscally favourable but socially costly trajectory: federally-retained revenue rose, the primary fiscal balance improved relative to the 2018-2022 baseline, but headline CPI inflation accelerated and household real-consumption proxies weakened in the 12-24 months post-removal. The pre-registered claim is that, in a synthetic-control design with a Sub- Saharan African oil-exporter donor pool (Angola, Algeria, Gabon, Republic of Congo, Equatorial Guinea), Nigeria's primary fiscal balance share of GDP improves by at least 1.5 percentage points 2023-2025 vs synthetic counterfactual AND CPI inflation rises by at least 6 percentage points more than the synthetic counterfactual. The null counter-claim is that Nigeria's fiscal improvement is statistically indistinguishable from the donor-pool path once oil-price terms-of-trade and naira devaluation are netted out — i.e. the subsidy reform did not deliver fiscal repair distinct from windfall mechanics.
  • Falsification rule: Not supported if EITHER (a) synth_did CATT on primary_fiscal_balance over 2023Q3- 2025Q4 is less than +1.5 percentage points of GDP at p_perm < 0.10, OR (b) the inflation acceleration relative to synthetic counterfactual is less than +6 percentage points cumulative, OR (c) both the fiscal and inflation effects are inside the placebo distribution (indicating the reform did not produce a detectable break).

Synthetic-control estimate

  • shape: synth_did
  • treated_country: NGA
  • event_year: 2023
  • n_donors: 3
  • donor_weights (top): {'AGO': 0.6937, 'DZA': 0.3063, 'COG': 0.0}
  • pre_rmse: 0.18548260748761344
  • pre_period_sd: 0.245083775361187
  • mean_post_gap: 0.3136971673850269
  • end_period_gap: 0.04969634417188373
  • post_period_years: [2023, 2024]
  • placebo_p_value: 1.0
  • n_placebos: 3
  • method: synthetic-control via NNLS, permutation inference

Variables resolved

  • world_bank_wdi:FP.CPI.TOTL.ZG; imf:PCPIPCH → cpi_inflation_yoy (outcome, n=9066)

Generated by scripts/run_synth_did.py at 2026-04-30T10:15:29+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

Data-gated on IMF GFS quarterly fiscal series for Nigeria (often lagged) and CBN inflation data. The June-2023 naira float is a confound; the spec controls for it rather than excluding it because the political package was bundled. Run target after IMF Article IV 2025 update releases full-year 2024 fiscal data.

Authored framework. Read the transparency note.