1. Obtaining tariff-line data
Find authorityCustoms, finance ministry, gazette, parliament or legally governing regional authority.
Acquire complete sourceWorkbook, PDF, API, portal tree or enacted base-plus-amendment chain.
Normalize without rewritingPreserve printed code, description, rate text, unit, scope, locator and source metadata.
Identify tariff linesExclude headings, page artefacts, exact repeats and preferential-rate records.
Verify the extractionRecord the source-file hash; check code length and structure, chapters, schedule sections and known defects.
Preserving source rows. Every HS-coded source row is retained before duty classification, including prohibited, restricted, textual, conditional and blank duty cells. A row is not discarded merely because its duty cannot be expressed as one percentage. Extraction checks also compare each recognized schedule with the corresponding six-digit HS classification to show whether any coded products were missed.
Every reported tariff rate comes exclusively from the issuing government or a legally governing regional authority. World Tariff Profiles are used only for comparison and never supply, replace or imply a tariff rate. An official schedule may still be retained as a reference when it is old, incomplete or lacks evidence that it applies in 2026; it remains visibly marked “not validated for 2026.”
2. Checking 2026 applicability
AFFIRMATIVE APPLICABILITY
Current law or operational date
A current portal date, enacted instrument, explicit carry-forward clause, or complete official amendment chain must establish that the rates were in force at the release reference date, 28 August 2026. This is point-in-time validity, not a claim that every rate remained unchanged throughout the whole calendar year.
COMPLETE TARIFF-LINE COVERAGE
No silent gaps
All operative tariff codes and rate scopes must be present. Parent headings, national subdivisions, duplicate printed rows and special Chapter 00/98 regimes are reviewed explicitly.
NO IMPUTATION
Published duties stay published
Missing rates are not filled from neighbouring lines, preferences, partner data or historical schedules merely to make a schedule appear complete.
UNVERIFIED IS NOT CURRENT
Reference schedule ≠ current schedule
If the legal chain or completeness evidence remains unresolved, classification statistics may be shown with a caution, but the economy remains not validated for 2026.
Customs unions and shared territories. A union schedule is used only where it legally governs the economy, and national amendments or deviations are applied before validation. Trade denominators must match the tariff territory: combined-territory evidence is identified as such and counted once in grouped estimates, while country profiles may assign the same governing schedule to each covered economy. Rates or trade are never copied between members merely because they share a customs union.
3. Tariff-form classification
Every distinct coded tariff-line product or scope receives one primary category: duty-free, positive ad valorem, specific, compound, alternate/mixed, seasonal/range/conditional, prohibited, restricted/non-rate, other/untyped, or blank/unresolved. Quota, in-quota and out-of-quota status is recorded separately.
Count denominator. A tariff line is one distinct coded product or legally separate rate scope—not every source row and not every printed heading. Rules that apply to all imports are retained separately from coded tariff-line counts.
4. AVE calculation using official tariff-line trade
Duty-free and positive ad-valorem rates enter directly. For the formulas below, V is customs import value, Q is the matching quantity in the legal duty unit, d is the specific duty amount per q0 units, f converts the duty currency into the value currency, and t is an ad-valorem percentage. Every published operator is applied in its legal order.
Unit-value validity and plausibility checks. Value and matching legal-unit quantity must be positive, and the customs value must represent at least US$2,500 after currency conversion for this diagnostic. Where a same-unit world HS6 comparison is available, the release computes
uTL = VUSD/Q,
rho = uTL / world HS6 unit value, and the AVE implied by the world unit value. An observation is excluded from the official-tariff-line-trade series when
rho > 1.40 and the world-denominator AVE exceeds the tariff-line AVE by more than 20 percentage points. Ratios below 0.20 or above 5.00 are also excluded as a conservative check. The original calculation remains in the audit data; the all-method series uses a same-unit world HS6 denominator or, if unavailable, a clearly labelled median from comparable lines. Gross weight is never treated as net weight. Lines without a comparable external unit value can remain in the official-trade series, with the absence of a comparison recorded. The sequence used to select an alternative denominator follows the
WITS AVE methodology.
Excluded official-trade example — Canada 07061031: the published compound rate gives 4.2230% from only C$801 and 190 kg. The observation is below the US$2,500 information threshold, so 4.2230% is retained in the audit data but excluded from the official-trade series; the all-method series uses the same-unit world HS6 estimate of 5.0230%.
Published-formula verification. Duties stated per 1,000 kg or items are normalized with q0 = 1,000. Additive specific terms sharing the same mass basis are first converted to one per-kg duty and summed. Only extraction or parsing errors supported by source evidence are corrected, and each original value is retained in the row-level audit file; correctly normalized formulas are not changed.
Currency and legal-unit verification. Every selected AVE is checked against the published duty currency, the customs-value currency, the annual conversion-factor direction and the legal duty unit. Same-currency factors cancel and are never rescaled. A trade quantity is accepted only when it measures the legal base: ordinary litres cannot stand for litres of pure alcohol; ordinary net kilograms cannot stand for dry matter, drained weight or total-alcohol mass; and product mass cannot stand for sugar content, metal content, polarization degrees or proof litres. If the required denominator is unavailable, the AVE is excluded from the official-trade series and any value in the all-method series is identified as an estimate. In Fiji this corrects the Fiji-dollar conversion and prevents the wrong quantity from being used for all 12 alcohol-content lines. In the United States, six metal-content duties remain in the official-trade series because the official Census QTY2 field supplies content kilograms. In Turkmenistan, one published per-gram duty is corrected after it had been treated as per kilogram.
Cross-year HS classifications, unit equivalence, combined customs territories and exchange rates are documented in the source and calculation notes. Missing inputs are not inferred from the resulting AVE.
Official-trade AVEs must be reproducible. Each released value must be recomputable from the structured duty, trade and exchange-rate fields. Prose alone is not treated as proof.
5. Estimates when official tariff-line trade is unavailable
Where an AVE using official tariff-line trade is unavailable, the all-method series selects the first estimate that passes the stated checks in a fixed evidence sequence. Each row below identifies the evidence used, its calculation and the exact formula. Qualifications concerning continuity, exchange rates and data quality are retained in the source and calculation notes. The original candidate, selected estimate and reason for exclusion remain separate so the decision can be reviewed.
Large AVEs and the optional 249% sensitivity. The published duty and selected raw estimate are never overwritten. Solomon Islands 24013000, for example, has a selected global-HS6 estimate of 22,966.3375% from its published SBD2,558.823/kg duty. A separate capped sensitivity stores 249% for analyses that would otherwise be dominated by that observation, while log(1 + AVE/100) compresses its scale without changing its rank. These are additional analytical variables, not alternative claims about the legal tariff. The 249% threshold is the 99.5th percentile of clean validated AVEs; results should be compared across raw, capped and logarithmic specifications.
6. Six-digit MFN averages in H4, H5 and H6
The strict official-only six-digit files use the same selected government tariff schedules as the country profiles. H4 denotes HS 2012, H5 denotes HS 2017 and H6 denotes HS 2022. These labels describe the target HS classification for the summary, not necessarily the classification printed in the original national schedule. The separately marked provisional extension described below does not meet the strict official-source standard and must be treated as an analytical scenario.
ONE VALUE PER NATIONAL TL
Tariff-line input
Each national tariff line contributes one percentage: zero for a duty-free line, its published percentage for a positive ad-valorem line, or the released line-level AVE for a non-ad-valorem duty. A line with no defensible percentage is excluded from the average but remains in the coverage counts.
UNWEIGHTED TL MEAN
Average within HS6
The HS6 value is the arithmetic mean of the available national tariff-line percentages assigned to that six-digit product. It is not trade weighted. National subdivisions receive equal weight. Legally separate seasonal or product-scope lines remain separate observations; paired quota tiers are retained separately, but only the ordinary/out-of-quota tier contributes to the MFN line value.
OFFICIAL HS CONCORDANCES
Comparable H4, H5 and H6 files
Codes are converted with the official United Nations Statistics Division conversion and correlation tables. Correlation sheets are included so that unchanged codes are not lost. If a source does not declare its HS revision, the result is labelled “derived (UNSD concordance)” with match diagnostics; an ambiguous revision remains unresolved. Where a government tariff portal publishes a fuller product list than its rate results, that list may identify the HS revision but never supplies a tariff rate.
Aggregation across HS revisions. When several source HS6 codes map to one target code, their averages are combined using their national tariff-line counts as weights; this preserves the underlying unweighted tariff-line mean. When one source code maps to several target codes, the source observation is repeated in each target code because the concordance does not identify which national subdivisions belong to which descendant. Those repeated target observations are suitable for product-level comparison but must not be summed across target codes.
All-products legal rules. A duty that applies to all products is expanded across an H4, H5 or H6 code universe only when the official legal source states that scope and all published exceptions have been applied. A missing product code is never assigned a rate merely to complete the target HS list.
Coverage is reported with separate denominators. The diagnostics show: national tariff lines eligible for HS6 assignment; lines successfully assigned; distinct source HS6 codes represented; lines with a direct rate or released AVE; non-ad-valorem lines without an AVE; blank, prohibited and other non-rate lines; and target H4, H5 or H6 codes with a calculable average relative to the full standard universe—5,205 H4 codes, 5,387 H5 codes and 5,612 H6 codes. A schedule may therefore be fully acquired even though some HS6 averages are unavailable, and a concorded target file may contain fewer than all target HS6 codes without implying that tariff lines were omitted.
7. Tariff-rate quotas
A published in-quota or out-of-quota AVE is a tier rate, not an effective blended rate. For the legal MFN series and its default simulation scalar, TINA uses the out-of-quota rate. This follows the WTO tariff-data convention, under which MFN tariffs for tariff quotas are the rates applied to quantities outside the quota. The published in-quota rate is retained as a separate scenario observation and is never averaged into the ordinary MFN rate merely because both tiers are printed in the schedule.
No-quantity fallback. If utilization cannot be measured for the same quota, product, unit and period, TINA does not omit the tariff and does not invent a 50/50 or fill-rate blend. The official out-of-quota MFN rate remains the default simulation treatment; the published in-quota rate remains available as a sensitivity. For an out-of-quota non-ad-valorem formula, the ordinary AVE evidence ladder applies. If its denominator fails the quality gate but the legal formula contains an ad-valorem floor, that floor may be released as an explicitly labelled lower-bound scalar. If neither an exact denominator nor a statutory floor exists, the last-resort simulation scalar is a flagged robust median from the narrowest available official-duty donor pool (same reporter and HS6, then HS4 and duty form, then wider peers). It is labelled modelled/low-confidence and never represented as an exact statutory percentage.
Observed effective incidence is released only as a separate analytical scenario. The hierarchy is: (1) disjoint tier customs values and duties, value-weighted; (2) disjoint tier quantities, shown only as an equal-unit-value proxy; or (3) WTO AGIMS in-quota imports combined with a separately validated total-import denominator for the exact quota, product, unit and period, shown like (2) only as a quantity-share/equal-unit-value proxy. A fill rate is quota use divided by quota capacity—it is not, by itself, the in-quota share of total imports. The official-data calculation criteria currently support 126 independent Swiss-customs-territory HS6 groupings from 370 TN8 observations; they are not asserted to be legal quota-pool utilization groups.
Official references: WTO Tariff Analysis Online help; WTO tariff-rate quota dataset; WTO Consolidated Tariff Schedules, Section 1B; the WTO tariff-quota explanation; and UNCTAD's AVE methodology, which uses progressively wider official import-unit-value evidence when tariff-line denominators are unavailable. TINA's donor median is a disclosed simulation-only extension for formulas whose legal unit cannot be matched to trade quantities.
8. Country product tables
The country tables use 22 product groups: ten Agricultural and twelve Non-agricultural groups. These presentation groups are separate from the six-digit H4, H5 and H6 files described above.
