Methodology

How the index is built — from raw scholarly records to comparable national measures. Every figure is computed in-house from first principles on a corpus we assemble and maintain ourselves.

Approach

The index does not adopt any external indicator, score or ranking. We take scholarly records, assign each work to the authors, institutions and nations that produced it, and build every measure from that base.

The questions we ask of the record — how much a nation produces, how far its work travels, how much it cites itself, how its standing shifts over time — are not unique to us, and we reference related work where it is relevant. The contribution is the pipeline: a single, consistent route from individual works to national measures, computed the same way for every nation and every field, so that any two readings can be set against each other on a common footing.

Sources

The corpus is assembled from several primary sources rather than a single database. No source supplies a finished metric; each contributes records, which we process ourselves.

No source is treated as authoritative on its own. Records are reconciled across sources, with conflicts resolved against the most complete and verifiable record rather than by precedence of provider.

The pipeline

Every work passes through the same sequence before it contributes to any national measure.
  1. Ingest and reconcile. Records are drawn from all primary sources and merged. The same work appearing in more than one source is matched and deduplicated to a single canonical record.
  2. Disambiguate. Authors, institutions and venues are resolved to single identities. Author disambiguation is the most consequential step in the pipeline — every downstream national figure depends on it — and is treated accordingly.
  3. Attribute fractionally. Each work is allocated by author share. A paper with four authors contributes a quarter to each, and those fractions roll up to institutions and nations. A work is never counted once per nation; credit sums to one across all contributors.
  4. Map to fields. Works are mapped to one or more research fields, allowing every national measure to be read whole or sliced to a single field.
  5. Resolve the citation graph. Citations are linked work-to-work across the reconciled corpus. This reference graph is the only external structure the citation measures rest on; the measures themselves are computed from it directly.
  6. Compute and rebase. National measures are computed from the attributed records and the citation graph, over rolling multi-year windows, and rebased to a common scale so that levels and movement can be compared across nations, fields and time.

Counting conventions

Fractional credit. All counts are fractional by author share, not whole-counted per nation. This avoids inflating multi-national collaborations and keeps national totals additive.

Field weighting. Measures are normalised by field so that a work in a heavily cited discipline does not outweigh one in a sparsely cited discipline. Comparison is always like with like.

Rolling windows. Volume and movement are read over rolling multi-year windows rather than single years, so that trajectory can be read alongside scale without single-year noise.

Rebasing. Time series are rebased to a common reference point. Where a measure is a share of a global total, this is stated explicitly, since a share can fall while the absolute level rises.

Limits and caveats

The measures are only as good as the record they are built on, and the record is incomplete in known ways.

Coverage is uneven. Bibliographic coverage varies by language, discipline and region. Specialist datasets and direct submissions narrow the gaps but do not close them. Counts are indicative, not exhaustive.

Disambiguation carries error. Author and institution resolution is imperfect at scale. Because attribution is load-bearing, residual error propagates into national figures; we treat this as the primary validity risk and report at resolutions where it is tolerable.

Field boundaries are choices. How a field is delineated affects its results. For field-level indices the definition is published alongside the figures, so the boundary can be inspected rather than assumed.

Open records under-measure closed research. Work that is classified, commercial or otherwise unpublished does not enter the corpus. In strategically sensitive fields this can understate real national capability, and the measures should be read as covering the open research record, not the whole of national activity.

Small slices are volatile. At narrow field or short time slices, counts fall and figures grow sensitive to a handful of works. Series below a minimum volume are shown with wider bands or withheld.

Openness

The method and index definitions are published in full; the intent is that any figure can be traced back to the way it was built. Underlying data is made available to the extent that coverage and licensing allow, sufficient for the published measures to be checked. Full documentation lands alongside each data release.