Methodology

Every figure published here is computed from an open citation graph by a stated formula. Nothing is estimated, nothing is assigned by judgement, and nothing is adjusted by hand.

Where the citation data comes from

Citations are taken from OpenAlex, an open catalogue of scholarly works released into the public domain under CC0. It supplies, for each indexed item, the number of citations received in each year and the item's own reference list.

This matters for a reason worth stating plainly: a citation window cannot be computed from a lifetime citation total. A metric that counts citations received in a particular period needs the year-by-year breakdown, and any figure claiming to be a windowed citation rate without it is not what it says it is.

The formulas

Citations per item (four-year window)

Citations received in Y-3…Y by items published in Y-3…Y, divided by those items.

value = citations(Y-3…Y → items published Y-3…Y) ÷ items(Y-3…Y)

This is the CiteScore formula as published by Elsevier, applied unchanged.

Citations per item (two-year window)

Citations received in year Y by items published in Y-2…Y-1, divided by those items.

value = citations(Y → items published Y-2…Y-1) ÷ items(Y-2…Y-1)

h-index

The largest h such that h indexed items have each been cited at least h times.

Self-citation rate

References from this journal that point at this journal, over all its references. Withheld below 60% reference coverage, because a partial reference graph yields a lower bound rather than a rate.

value = references(this journal → this journal) ÷ references(this journal → anywhere)

Reference coverage

Items with a deposited reference list, over all indexed items.

Uncited items

Items with no recorded citations, over all indexed items.

International collaboration

Items with authors from more than one country, over items with a known author country.

Field quartile

Journals are ranked by citations per item within their broad subject field, and the ranking is divided into four equal parts. Q1 is the most cited quarter.

Quartiles are assigned only where a field holds enough ranked journals for a quarter to mean anything, and a journal is ranked only once it has published enough items in the window. Below those floors a journal is listed with its metrics and no quartile.

What the denominator is

Denominators count citable item types — research articles and reviews. Citations to any item type, including editorials and letters, still count in the numerator. This follows the same convention Elsevier uses, and it is the convention that makes the figure comparable with a published CiteScore rather than inflated relative to one.

The numerator and denominator are printed next to every value on every journal page. A publisher who disagrees with a figure can check the arithmetic against their own records.

Where a figure is withheld

OpenAlex holds a reference list only where the publisher deposited one. Across the journals indexed so far that is between a fifth and a half of items. A self-citation rate divided out of a partial reference graph is a lower bound, not a rate, so it is withheld wherever reference coverage falls below 60%, and the coverage figure is published alongside.

A blank on this site means the evidence does not support a number. It does not mean zero.

Conflict of interest

This index is operated by ACS Publisher, which also publishes journals. Those journals are marked on their entries. The code that computes metrics does not read that marking: an operator-published journal goes through the identical calculation, from the identical data.

The eligibility decision is a human judgement and cannot be made conflict-proof by code, so it is handled by separation instead — see About.

Recomputing this yourself

The citation data is public, the formulas are above, and the denominators are published. Any figure here can be reproduced independently. That is the point of publishing them this way.

Metrics currently shown are for 2024.