Wiki · Persistent identifier

Persistent identifier policy

For peer reviewers, cite-checkers, institutional libraries, and regulators who need to know whether a Policy Window citation will still resolve in 5 years, 25 years, or after the project ends.

Last updated: 2026-05-30 (iter-312).

1 · Today: committed-stable URLs + `?asOf=` snapshot pinning

Each article's canonical URL at policywindow.org/wiki/[slug] is committed-stable. Slugs do not change after publication; if a topic is renamed, the old slug remains as a 308 redirect and the rename is recorded in /wiki/changelog.

Citation by version uses the ?asOf=YYYY-MM-DD URL parameter. When set, the read path queries the ArticleRevision table for the most-recent snapshot captured at-or-before the requested date and renders against that historical state. The green "Pinned snapshot" banner above the title confirms the article body is the frozen historical content. See methodology §6 for the implementation detail.

Honest gap:when no snapshot exists for the requested date (e.g., the article was created after that date), the read path falls back to the current catalog state and an amber "No snapshot available for that date" banner discloses the fallback. Snapshot capture is daily via CI; the oldest snapshot for any given article is the date immediately after the article was first published.

2 · DOI roadmap (Zenodo, Q4 2026)

Per-article + per-snapshot DOIs via Zenodo are committed for Q4 2026 (see /wiki/roadmap milestone Q4-26-DOI). When this lands:

Every existing article gets a retroactive DOI registered against the article's first-published snapshot.
Every future ?asOf= snapshot gets its own DOI registered at capture time.
The CiteThisWidget begins exporting DOIs as the primary identifier with the wiki URL as fallback.
Existing URL-based citations remain valid forever; the DOI addition is purely additive.

Why not sooner? Zenodo integration requires editorial board consensus on what constitutes a "version" for DOI purposes (every catalog deploy? every reviewed change? per quarter?). With the board at 1 of 6 slots filled, that decision is gated by editorial recruitment (see /wiki/editorial-board).

3 · Archival commitment (if the project ends)

Should Policy Window cease operation, the full catalog and its ?asOf= snapshot history will be archived to a neutral home with the same URL structure preserved as long as is technically feasible. Specific commitments:

Internet Archive Wayback Machine: we actively request indexing of every article + the catalog JSON / CSV endpoints. The catalog endpoints have been archived since 2026-Q2.
Source-code mirror: the public GitHub repository contains the full typed catalog data. A self-hoster can reconstruct the wiki from the repo + the ArticleRevision SQL dump.
Catalog data dumps: /wiki/catalog/json and /wiki/catalog/csv are CORS-open + downloadable. Researchers building secondary analyses are encouraged to archive periodic snapshots locally as a redundancy.
Zenodo DOIs(once registered Q4 2026) persist independently of Policy Window's operational status — the DOI Foundation is the authoritative resolver and Zenodo guarantees content retention beyond project lifetime.
30-day takedown notice: per terms of service §7, we won't suspend the public wiki in a way that breaks ?asOf= citation URLs without a 30-day notice posted on /wiki/changelog.

4 · What to cite today

Until DOIs land in Q4 2026, the recommended citation pattern is the ?asOf=YYYY-MM-DD URL. Example for a paper citing the EU AI Act article today:

Policy Window, "EU AI Act" (accessed 30 May 2026), https://policywindow.org/wiki/eu-ai-act?asOf=2026-05-30

The CiteThisWidget on every article surfaces this format plus six others (BibTeX, RIS, APA, Chicago, Harvard, OSCOLA, Bluebook). When DOIs ship, citations generated by the widget will include the DOI automatically.

5 · Comparison vs other persistent-ID standards

Standard	Policy Window status
URL stability	Live since 2026-Q2. Slug rename = 308 redirect; old URL preserved indefinitely.
Version pinning	Live since iter-310 followup (2026-05-29). `?asOf=YYYY-MM-DD` URL parameter; ArticleRevision-backed.
DOI (Zenodo)	Q4 2026 roadmap. Gated by editorial-board recruitment.
ARK (Archival Resource Key)	Not on roadmap. DOI via Zenodo provides equivalent guarantees for our use case.
Handle System	Not on roadmap. DOI routes through the Handle System so registering DOIs satisfies this dependency indirectly.
ROR (Research Organization Registry)	Pending PBC / nonprofit incorporation (Q4 2026 roadmap). ROR ID will be registered after legal entity exists.
Wikidata QID	Many of the underlying instruments + concepts carry Wikidata QIDs in their `externalIdentifiers` field. The wiki itself does not yet have a top-level QID; we'll register when it makes sense.

1 · Today: committed-stable URLs + `?asOf=` snapshot pinning

2 · DOI roadmap (Zenodo, Q4 2026)

Per-article + per-snapshot DOIs via Zenodo are committed for Q4 2026 (see /wiki/roadmap milestone Q4-26-DOI). When this lands:

Every existing article gets a retroactive DOI registered against the article's first-published snapshot.

Every future ?asOf= snapshot gets its own DOI registered at capture time.

The CiteThisWidget begins exporting DOIs as the primary identifier with the wiki URL as fallback.

Existing URL-based citations remain valid forever; the DOI addition is purely additive.

3 · Archival commitment (if the project ends)

Internet Archive Wayback Machine: we actively request indexing of every article + the catalog JSON / CSV endpoints. The catalog endpoints have been archived since 2026-Q2.

Source-code mirror: the public GitHub repository contains the full typed catalog data. A self-hoster can reconstruct the wiki from the repo + the ArticleRevision SQL dump.

Catalog data dumps: /wiki/catalog/json and /wiki/catalog/csv are CORS-open + downloadable. Researchers building secondary analyses are encouraged to archive periodic snapshots locally as a redundancy.

Zenodo DOIs(once registered Q4 2026) persist independently of Policy Window's operational status — the DOI Foundation is the authoritative resolver and Zenodo guarantees content retention beyond project lifetime.

30-day takedown notice: per terms of service §7, we won't suspend the public wiki in a way that breaks ?asOf= citation URLs without a 30-day notice posted on /wiki/changelog.

4 · What to cite today

Until DOIs land in Q4 2026, the recommended citation pattern is the ?asOf=YYYY-MM-DD URL. Example for a paper citing the EU AI Act article today:

Policy Window, "EU AI Act" (accessed 30 May 2026), https://policywindow.org/wiki/eu-ai-act?asOf=2026-05-30

5 · Comparison vs other persistent-ID standards

Standard

Policy Window status

URL stability

Live since 2026-Q2. Slug rename = 308 redirect; old URL preserved indefinitely.

Version pinning

Live since iter-310 followup (2026-05-29). ?asOf=YYYY-MM-DD URL parameter; ArticleRevision-backed.

DOI (Zenodo)

Q4 2026 roadmap. Gated by editorial-board recruitment.

ARK (Archival Resource Key)

Not on roadmap. DOI via Zenodo provides equivalent guarantees for our use case.

Handle System

Not on roadmap. DOI routes through the Handle System so registering DOIs satisfies this dependency indirectly.

ROR (Research Organization Registry)

Pending PBC / nonprofit incorporation (Q4 2026 roadmap). ROR ID will be registered after legal entity exists.

Wikidata QID

Many of the underlying instruments + concepts carry Wikidata QIDs in their externalIdentifiers field. The wiki itself does not yet have a top-level QID; we'll register when it makes sense.