IESET.
Hypotheses·trade·wits_tariff_cuts_import_variety_panel

Higher applied tariff rates predict lower imported product variety.

The mechanism is straightforward: tariff barriers make marginal HS6 product lines less economical to import, narrowing the range of foreign inputs and consumer goods available in the domestic market.

PARTIALengine/runs/wits_tariff_cuts_import_variety_panel

PARTIAL — coef=-0.000898, p=0.352 (above α=0.1); 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

When countries open more of the economy to trade and competition, do people end up with better long-run income or productivity outcomes?

plain answer

The evidence is suggestive but not decisive. coef=-0.000898, p=0.352 (above α=0.1); direction inconclusive

why it matters

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

how the test works

It compares 39 country or place units from 1988 to 2023, using a panel fe design, with fixed effects for country and year.

what was measured
What changed
  • Applied tariff
What we checked
  • Import hs6 product lines
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/wits_tariff_cuts_import_variety_panel
1007550250198820062023ARGAUSAUTBELBRACANCHE
illustrative sketch · run pending
No coefficients yet. When the model fires, this chart will show import_hs6_product_lines across 39 sampled countries over 1988–2023.
The shapes above are stylised — none of the lines are real data.
Placeholder for wits_tariff_cuts_import_variety_panel. Published chart will be generated from engine/runs/wits_tariff_cuts_import_variety_panel/chart_data.json.

Pre-registration

registration ordering unverified
first-spec commit 4c8ce8e · 2026-07-18T22:11:21Z
run generated · 2026-06-29T17:54:44Z
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.

Higher applied tariff rates predict lower imported product variety. The mechanism is straightforward: tariff barriers make marginal HS6 product lines less economical to import, narrowing the range of foreign inputs and consumer goods available in the domestic market.

Falsification criterion — what would disprove this

set before the run · honoured after

This hypothesis is considered falsified if:

SUPPORTED only if applied_tariff is negative at p<=0.10 with at least 300 observations and 20 countries. REFUTED if applied_tariff is positive at p<=0.10.

formal test & threshold
test:      panel_fe_wits_tariff_cuts_import_variety_panel
threshold: [object Object]

Method

Template
panel_fe
Fixed effects
country, year
Clustering
country
Sample
39 countries · 1988 – 2023
Evidence type
associational

Two-way FE screen of log import product lines on applied tariffs and trade scale controls.

Data

VariableSourceTransform
import_hs6_product_lines
outcome
wits:product_linestier 2
log
applied_tariff
treatment
wits:tariff_averagetier 2
level
export_hs6_products
control
wits:unique_hs6_productstier 2
log
import_value
control
wits:import_valuetier 2
log

● ready  · ● pending  · ● reconstruct-needed

Detailed result card

Result card — wits_tariff_cuts_import_variety_panel

Verdict: PARTIAL — coef=-0.000898, p=0.352 (above α=0.1); direction inconclusive

Pre-registration

  • Claim: Higher applied tariff rates predict lower imported product variety. The mechanism is straightforward: tariff barriers make marginal HS6 product lines less economical to import, narrowing the range of foreign inputs and consumer goods available in the domestic market.
  • Falsification rule: SUPPORTED only if applied_tariff is negative at p<=0.10 with at least 300 observations and 20 countries. REFUTED if applied_tariff is positive at p<=0.10.
  • Falsification test: panel_fe_wits_tariff_cuts_import_variety_panel

Estimate

  • Method: linearmodels.PanelOLS
  • Coefficient (treatment): -0.000898
  • Std error: 0.0009649
  • p-value: 0.352
  • Observations: 1030, countries: 39
  • Within R²: -0.227
  • Fixed effects: entity=True, time=True
  • Clustering: country

Variables resolved

  • wits:product_lines → import_hs6_product_lines (outcome, publisher=wits, n=5357)
  • wits:tariff_average → applied_tariff (treatment, publisher=wits, n=3806)
  • wits:unique_hs6_products → export_hs6_products (controls, publisher=wits, n=5308)
  • wits:import_value → import_value (controls, publisher=wits, n=14395)

Generated by scripts/run_panel_fe.py at 2026-06-29T17:54:44+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

Uses only May 2026 WITS bridge panels with normalized country-year structure.

Authored framework. Read the transparency note.