Licences
What you may reuse from this site, and on what terms. Upstream data keeps its source’s licence; the numbers and text Codex Populi computes itself are CC BY 4.0, as set out below.
Codex Populi’s own numbers — CC BY 4.0
Codex Populi’s own numbers are licensed CC BY 4.0: the accuracy measures it computes (error and rel_error in scores.csv.gz; mean bias, MAE, MAPE, medians, percentiles, counts and shares on /v1/accuracy), the changes and moves it computes (change, relChange and changePerYear from /v1/data?view=latest_change; move and relMove from /v1/accuracy?view=revision_moves), the text and counts of release notes and diffs, and the tags the site derives.
The projected and actual values in scores, values quoted in release notes and diffs (from/to), and the points the derived views quote (value, endValue, fromValue and toValue) are the named sources’ data and keep their licences: projected that of its source, actual that of un-wpp, and a quoted point that of the source or revision it comes from.
Display-only sources (IHME, WIC) appear only on this site: their scores, and any change, move, year, status or other figure derived from their data, are not covered and are not licensed for reuse.
Credit this line: Codex Populi, release <id>, https://codexpopuli.org/releases/<id>.
Legal code: creativecommons.org/licenses/by/4.0/
Reference lists — CC0 1.0
entities.csv and indicators.csv in every release are released under CC0 1.0. No credit is required.
manifest.json is not covered by CC0, because it carries release notes.
Releases published before these terms carry no statement in the bundle; the same grant applies to their reference lists.
Source data — each source’s licence
Values keep their source’s licence wherever they appear (/v1/data, charts, bulk files). /v1/sources lists every source’s licence id, including display-only ones, but no values.
| Source | Licence | Licence id |
|---|---|---|
| UN World Population Prospects | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| World Bank World Development Indicators | CC BY 4.0 | CC-BY-4.0 |
| Human Mortality Database | CC BY 4.0 | CC-BY-4.0 |
| UN World Population Prospects, 1998 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| UN World Population Prospects, 2000 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| UN World Population Prospects, 2002 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| UN World Population Prospects, 2004 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| UN World Population Prospects, 2006 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| UN World Population Prospects, 2008 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| UN World Population Prospects, 2010 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| UN World Population Prospects, 2012 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| UN World Population Prospects, 2015 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| UN World Population Prospects, 2017 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| UN World Population Prospects, 2019 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| UN World Population Prospects, 2022 Revision (archival) | CC BY 3.0 IGO | CC-BY-3.0-IGO |
| IHME Global Population Forecasts (2020, Lancet reference scenario) | IHME Free-of-Charge Non-Commercial User Agreement | LicenseRef-IHME-NonCommercial |
| Wittgenstein Centre Data Explorer, Version 1.0 (2013 vintage) | Custom (IIASA/WIC, unconfirmed) | LicenseRef-IIASA-WIC-Unconfirmed |
| Wittgenstein Centre Data Explorer, Version 2.0 (2018 vintage) | Custom (IIASA/WIC, unconfirmed) | LicenseRef-IIASA-WIC-Unconfirmed |
| Wittgenstein Centre Data Explorer, Version 3.0 Beta (2023 vintage) | Custom (IIASA/WIC, unconfirmed) | LicenseRef-IIASA-WIC-Unconfirmed |
| US Census Bureau International Database (IDB), 2025 revision (archival) | Public domain (17 U.S.C. §105) | LicenseRef-US-Gov-PD |
IHME and WIC values are shown on the site with attribution, for display only. They are not licensed for redistribution and are never in public /v1 responses (anonymous or keyed), MCP output or bulk files.
How a new source’s licence is assessed: Proposing a source.
News and research items
A research abstract is the publisher’s text, under the publisher’s terms.
Headlines link to the outlet.
The Conversation publishes its articles under CC BY-ND 4.0, so the site shows only their headline, author and a link — no summary. AI summaries of other items are Codex Populi’s and CC BY 4.0, to the extent Codex Populi holds rights in them; when reusing one, credit Codex Populi and the original item (title, outlet, link), which keeps its own licence.
Code
No licence is granted for the site’s source code. Ask the maintainers before reusing it.
How to cite: see the docs.