Method: the Business Conditions Index

A measure enters the Index's headline score only where it is compiled and published for all eleven markets, or for ten with a single stated exception. Measures with narrower coverage are published for the markets that report them and are not incorporated into the score.

The rule exists because the Index is a comparative instrument. A score constructed from different components in different markets would not support comparison between them, whatever its internal consistency. The rule is applied symmetrically: were a core series to cease publication for any one market, that component would leave the core for all eleven rather than be estimated for the market concerned.

Where a market is the single stated exception on one component, the remaining core weights are renormalised to sum to unity for that market, and its coverage is disclosed on its own row in every published table.

All five core components are compiled by the World Bank in the World Development Indicators. Each is mapped to a 0–100 scale on which fifty denotes the neutral reference, except trade engagement, which measures a level rather than a change.

Why a multiplier exists at all. The five components are published in different units. Real GDP growth runs across ASEAN from about −2% to +8%. Merchandise trade as a share of GDP runs from 36% to 180%. Add those raw numbers together and the larger digits decide the result by size alone, not by importance: trade openness alone would account for more than half of every market’s raw total, and for more than the whole of it in Lao PDR, the Philippines and Myanmar, where the other components are negative. Growth would contribute almost nothing — under 4% of the total even in Viet Nam, the fastest-growing market of the eleven. Brunei Darussalam, which ranks tenth of the eleven on the Index, would land in the top four: its economy grew 0.7% and its merchandise trade fell, but it trades at 110% of output and its capital reading moved on a very small base. The index would not measure business conditions; it would measure how much crosses a border relative to the size of the economy.

A multiplier is therefore a unit converter. It places a growth rate and a trade ratio on one 0–100 scale so that the published weights — 35% growth, 13% trade engagement — actually govern the outcome instead of being overridden by whichever statistic happens to carry bigger numbers. The shared neutral point does the same work: fifty means zero growth, no change in trade, no change in capital flows, inflation at the reference rate. Without a common anchor, an average across the five would mean something different for each of them.

Each mapping is that neutral reference plus a multiplier applied to the published statistic. Growth momentum is 50 + 5 × growth %. A market growing at zero scores fifty; each percentage point of growth adds five index points. Viet Nam grew 8.02% in 2025 and scores 90.1; Myanmar contracted 2.02% and scores 39.9.

Why five, and not eight or twenty. The size of the multiplier is not a preference. It is bounded at both ends, and the binding constraint is the top of the scale. A score cannot exceed one hundred, so a multiplier of k saturates at a growth rate of 50 ÷ k:

Viet Nam grew 8.02% in 2025, so the largest multiplier that does not clip the observed set is 6.23. Five is the largest round number beneath that ceiling, and it leaves headroom to 10% growth — enough for a market to accelerate for several years before the scale ceases to separate it from its neighbours. The multiplier is chosen, but it is chosen inside a range the data leaves open, and the arithmetic above can be repeated by any reader.

A stated revision trigger. That headroom is finite. If any market records growth above 10%, the growth component saturates and stops distinguishing between the fastest economies. Viet Nam at 8.02% is already inside two percentage points of it. Should a market cross that threshold, the multiplier is revised, the change is published as a change to this note, and the affected prior figures are restated.

Three provisions govern their use:

• The multipliers were fixed before any score was computed, and are not adjusted between editions in response to results. A change to any multiplier is a change to the method, published as such, with the prior series restated.
• The underlying statistic is published beside every score. A reader who prefers a different scaling can apply it to the published inputs and obtain a complete alternative set of scores.
• A sensitivity test accompanies every edition. Each edition re-computes all eleven scores under alternative multiplier settings — halved, doubled, and with the growth multiplier varied independently — and reports how far the resulting ranking departs from the published one.

The sensitivity test establishes whether the result is an artefact of the scaling chosen. In the current edition, halving or doubling every multiplier displaces no market by more than three positions and leaves the leading four unchanged as a set. The order within that four is not stable: Viet Nam leads as published, and Malaysia leads under doubled multipliers and under both the growth-heavy and growth-light settings. The membership of that leading group is therefore a property of the underlying statistics rather than of the scaling applied to them; the rank of any one market inside it is not, and should be read with the table below.

The following measures were assessed against the coverage rule. Those designated supplementary are published per market where they exist and are excluded from the score; those designated excluded are not published in either instrument.

The Index therefore contains no survey-based input. The distinction matters to how the instrument is named and read: it measures recorded conditions and activity, not reported sentiment. The Purchasing Managers' Index, which is the region's only survey-based reading, is published alongside the score for the seven markets that have one.

Every input carries one of three verification levels, recorded in the published data and shown on the page where the distinction affects how a figure should be read.

• Primary — the issuing body's own release, page or file was obtained and read.
• Secondary — a named publication reporting the issuing body, where the body's own release could not be obtained. The reason it could not be obtained is recorded against the figure.
• Gap — no figure is published by any body located.

Figures at secondary level are identified as such wherever they appear. Where primary access is subsequently obtained, the verification level is updated and the change is recorded, whether or not the figure itself changes.

The Business Conditions Index is annual. All five core components are annual series. The Index is labelled with the reference year it describes and is refreshed when the compiling authority publishes a new vintage, which has historically fallen between August and September.

A quarterly companion covers within-year movement. Merchandise trade is the only measure published at monthly or quarterly frequency by an issuing body in all eleven markets, and it is the basis of the quarterly reading: the year-on-year change in the eleven markets' combined merchandise trade. Quarterly GDP is compiled in seven markets and is reported as a seven-market reading, never aggregated to eleven.

The publication date is set by the slowest reporting authority in each cycle, which places it at the fifteenth day of the third month following the close of each quarter.

Carry-forward

Where an authority has not yet published, the figure for the preceding period is shown with its true reference period and the date on which the new figure is expected. It is never re-dated. A regional aggregate is published only when all constituent markets have reported; if published earlier it is marked provisional with the number of reporting markets stated, and reissued when complete.

What the Index does not measure

• Sentiment or expectations. The score contains no survey input.
• Services and the informal economy. Both trade components are merchandise-only.
• Movement within a year. All core components are annual, and vintages differ between markets on the capital-flow component.
• Volume as distinct from price. Trade is measured in current US dollars.

Revision policy

Revisions by a compiling authority flow through the published calculation without adjustment; every input records the date on which it was obtained. A change to a component, a weight, a multiplier or a threshold is a change to this note, is published as such, and is accompanied by a restatement of the affected prior figures. Corrections to a published figure are issued with the date of correction and a statement of what changed.

Circumstances that would alter published figures include: a revision by a compiling authority; the arrival of a current-year value for a market previously a year behind; the discontinuation of a core series for any market, which would remove that component from the core for all eleven; the first compilation of a series for a market currently outside coverage; and the publication of a regional series meeting the coverage rule, which would be assessed against the same test.

Each row below re-computes all eleven scores with a different scaling constant and compares the resulting order against the published one. Doubling or halving every multiplier moves no market more than three places, and the mean displacement stays below one. The membership of the leading four is therefore a property of the underlying statistics rather than of the scaling applied to them. The order inside that four is not: read the right-hand column before relying on any single market’s rank.