IESET.
Hypotheses·labour·demo_fertility_decline_growth_slowdown_panel

Across countries 1980-2023, sustained declines in the total fertility rate below 2.1 are followed within 20-30 years by significant slowdowns in real GDP per capita growth, mediated by working-age population share.

The mechanism predicts a panel association between TFR measured at year t and the per-capita growth rate observed at t+20 to t+30, controlling for initial income, capital deepening, and human-capital stock. The effect is hypothesised to operate primarily through the demographic-dividend reversal channel rather than innovation-decay or savings-glut channels.

PARTIALengine/runs/demo_fertility_decline_growth_slowdown_panel

PARTIAL — coef=+0.8426, p=0.516 (above α=0.05); direction inconclusive

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. coef=+0.8426, p=0.516 (above α=0.05); direction inconclusive

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 41 country or place units from 1980 to 2023, using a panel fe decomposition design, with fixed effects for country and year.

what was measured
What changed
  • Total fertility rate
Possible pathway
  • Working age population share
  • Dependency ratio total
What we checked
  • Real income per capita growth
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_fertility_decline_growth_slowdown_panel
1007550250198020022023USAGBRDEUFRAITAESPJPN
illustrative sketch · run pending
No coefficients yet. When the model fires, this chart will show real_gdp_per_capita_growth across 41 sampled countries over 1980–2023.
The shapes above are stylised — none of the lines are real data.
Placeholder for demo_fertility_decline_growth_slowdown_panel. Published chart will be generated from engine/runs/demo_fertility_decline_growth_slowdown_panel/chart_data.json.

Pre-registration

registration ordering unverified
first-spec commit 4c8ce8e · 2026-07-18T22:11:21Z
run generated · 2026-06-29T17:53:34Z
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.

Across countries 1980-2023, sustained declines in the total fertility rate below 2.1 are followed within 20-30 years by significant slowdowns in real GDP per capita growth, mediated by working-age population share. The mechanism predicts a panel association between TFR measured at year t and the per-capita growth rate observed at t+20 to t+30, controlling for initial income, capital deepening, and human-capital stock. The effect is hypothesised to operate primarily through the demographic-dividend reversal channel rather than innovation-decay or savings-glut channels.

Falsification criterion — what would disprove this

set before the run · honoured after

This hypothesis is considered falsified if:

SUPPORTED if coefficient on TFR(t-25) on per-capita growth is negative and significant at p<0.05 with a magnitude such that a 1-child decline in TFR predicts at least 0.5pp lower annualised growth 25 years later, AND the working-age-share channel accounts for at least 40 percent of the implied effect via mediation decomposition. REFUTED if coefficient is insignificant or wrong-signed, or if working-age-share channel <15% of effect.

formal test & threshold
test:      panel_fe_lagged_tfr_growth_with_mediation
threshold: coef_tfr_lag25 < 0 AND p_value < 0.05 AND mediation_share_wap >= 0.40

Method

Template
panel_fe_decomposition
Fixed effects
country, year
Clustering
country
Sample
41 countries · 1980 – 2023
Evidence type
associational

Two-way FE panel of 5-year-averaged growth on lagged TFR (20-25-year lag) plus decomposition into working-age-share contribution. Newey-West HAC SEs alternative.

Data

VariableSourceTransform
real_gdp_per_capita_growth
outcome
world_bank_wdi:NY.GDP.PCAP.KD.ZGtier 2
level
total_fertility_rate
treatment
world_bank_wdi:SP.DYN.TFRT.INtier 2
level
working_age_population_share
channel
world_bank_wdi:SP.POP.1564.TO.ZStier 2
level
dependency_ratio_total
channel
world_bank_wdi:SP.POP.DPNDtier 2
level
log_initial_gdp_per_capita
control
world_bank_wdi:NY.GDP.PCAP.PP.KDtier 2
log
tertiary_attainment
control
world_bank_wdi:SE.TER.CUAT.BA.ZStier 2
level
capital_per_worker
control
pwt:rkna_per_emptier 3
log

● ready  · ● pending  · ● reconstruct-needed

Detailed result card

Result card — demo_fertility_decline_growth_slowdown_panel

Verdict: PARTIAL — coef=+0.8426, p=0.516 (above α=0.05); direction inconclusive

Pre-registration

  • Claim: Across countries 1980-2023, sustained declines in the total fertility rate below 2.1 are followed within 20-30 years by significant slowdowns in real GDP per capita growth, mediated by working-age population share. The mechanism predicts a panel association between TFR measured at year t and the per-capita growth rate observed at t+20 to t+30, controlling for initial income, capital deepening, and human-capital stock. The effect is hypothesised to operate primarily through the demographic-dividend reversal channel rather than innovation-decay or savings-glut channels.
  • Falsification rule: SUPPORTED if coefficient on TFR(t-25) on per-capita growth is negative and significant at p<0.05 with a magnitude such that a 1-child decline in TFR predicts at least 0.5pp lower annualised growth 25 years later, AND the working-age-share channel accounts for at least 40 percent of the implied effect via mediation decomposition. REFUTED if coefficient is insignificant or wrong-signed, or if working-age-share channel <15% of effect.
  • Falsification test: panel_fe_lagged_tfr_growth_with_mediation

Estimate

  • Method: linearmodels.PanelOLS
  • Coefficient (treatment): +0.8426
  • Std error: 1.294
  • p-value: 0.516
  • Observations: 358, countries: 34
  • Within R²: 0.0285
  • Fixed effects: entity=True, time=True
  • Clustering: country

Variables resolved

  • world_bank_wdi:NY.GDP.PCAP.KD.ZG → real_gdp_per_capita_growth (outcome, publisher=world_bank_wdi, n=13897)
  • world_bank_wdi:SP.DYN.TFRT.IN → total_fertility_rate (treatment, publisher=world_bank_wdi, n=14445)
  • world_bank_wdi:SP.POP.1564.TO.ZS → working_age_population_share (decomposition_channels, publisher=world_bank_wdi, n=16965)
  • world_bank_wdi:SP.POP.DPND → dependency_ratio_total (decomposition_channels, publisher=world_bank_wdi, n=16935)
  • world_bank_wdi:NY.GDP.PCAP.PP.KD → log_initial_gdp_per_capita (controls, publisher=world_bank_wdi, n=8325)
  • world_bank_wdi:SE.TER.CUAT.BA.ZS → tertiary_attainment (controls, publisher=world_bank_wdi, n=1403)

Variables missing data

  • pwt:rkna_per_emp (controls, name=capital_per_worker) — vintage not on disk

Generated by scripts/run_panel_fe.py at 2026-06-29T17:53:34+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

Routes through WDI; PWT capital-per-worker control is data-gated on rkna availability.

Authored framework. Read the transparency note.