Dataset structured data + Google Dataset Search for the evidence catalogue and timeline

Harvested 2026-10-30 (skills harvest run). Topic check: "dataset search" and "@type":"Dataset" had 0 hits in INDEX.md and the skill files. The only nearby skill is data-led-digital-pr-heritage-dataset-pitch.md, which covers pitching a dataset to journalists, not markup.

Why it matters (numbers, primary sources)

• Google Dataset Search finds datasets by crawling the web for schema.org Dataset (or DCAT) markup. Sizes over time: 25 million datasets at public launch (Google blog). 28 million from 3,700+ sites in March 2020 (Benjelloun, Chen & Noy, "Google Dataset Search by the Numbers", arXiv 2006.06894, read). 45 million from 13,000 sources (Sostek et al., Harvard Data Science Review 2024, abstract read).
• The same 2020 paper (read) found that 37% of URLs carrying dataset metadata in June 2019 had lost the metadata or were gone by March 2020. Google's authors recommend persistent identifiers (DOI, compact identifiers) in identifier / sameAs.
• From the 2024 user study (abstract read): the open approach brings mixed, uneven datasets, and users struggle to make sense of them. Good descriptions and clear titles are what tell a dataset apart.
• Practitioner traffic numbers: none found this run. Google's own examples are science and government data. Treat this as a cheap discovery surface for researchers, students and AI tools that read schema, not as a proven traffic channel. Measure it before claiming any effect.

The rules (Search Central, Dataset structured data page, read 2026-10-30)

• Required: name (unique and descriptive, e.g. "Snow depth in the Northern Hemisphere", not a bare "Data") and description (50 to 5,000 characters; Markdown is allowed; use \n for new lines in JSON-LD).
• Recommended: url, sameAs, identifier (DOI/ARK), keywords, license (a URL), isAccessibleForFree, creator (Organization/Person, with sameAs where possible), temporalCoverage (ISO 8601 interval, e.g. 1841/1987), spatialCoverage (Place with geo), distribution (DataDownload with encodingFormat + contentUrl), includedInDataCatalog, hasPart / isPartOf, variableMeasured, version, dateModified.
• The markup describes the dataset (its metadata: what it covers, who made it, which variables). It does not carry the data values.
• Validate with the Rich Results Test, then watch the Search Console Dataset enhancement report. Data catalogues can use DataCatalog with dataset entries.
• Datasets show in Dataset Search (datasetsearch.research.google.com), and sometimes in Google Search dataset features.

How-to (one afternoon, no tools to install)

1. Pick 2 to 4 real tables we already build: e.g. the evidence catalogue index (id, date, type, holder, page URL), the research timeline events (date, category, source id), the /wales/qa/ question log (date asked, institution, status; the build already emits /qa/api/qa.json), and the furniture catalogue (FUR ids, room, image links).
2. Publish each as a stable CSV and JSON at a versioned URL (e.g. /data/evidence-catalogue.csv), kept at the same path forever. The 37% churn finding is the reason.
3. Give each a landing page (one per dataset) with a human summary, column list, coverage dates, licence, "how to cite", and the download links. Put the Dataset JSON-LD on that page only, never on every page.
4. Licence: only for our own compiled metadata (dates, ids, categories, our summaries). Never license archive images or third-party transcriptions; see archive-image-permission-terms-ai-animation-paid-versions.md. CC BY 4.0 is the usual choice because it requires citation.
5. Optional DOI: deposit a frozen version on Zenodo (zenodo-doi-scholar-argentine-repositories.md) and put the DOI in identifier and sameAs. That gives the persistent identifier Google's authors recommend.
6. Validate in the Rich Results Test, add the landing pages to the sitemap, and request indexing in Search Console. After 2 to 4 weeks, search Dataset Search for "Llandough" and "Great House Farm".

Template (fill per dataset):

{"@context":"schema.org
 "name":"Llandough Great House Farm evidence catalogue, 1841-1987",
 "description":"Index of catalogued records ... (50-5000 chars)",
 "url":"cedwyn.bucklerfamily.estate
 "keywords":["Llandough","Vale of Glamorgan","farm history","land records"],
 "license":"creativecommons.org
 "isAccessibleForFree":true,
 "creator":{"@type":"Organization","name":"Cedwyn"},
 "temporalCoverage":"1841/1987",
 "spatialCoverage":{"@type":"Place","name":"Llandough, Vale of Glamorgan, Wales"},
 "variableMeasured":["record date","record type","holding institution"],
 "distribution":[{"@type":"DataDownload","encodingFormat":"text/csv","contentUrl":"cedwyn.bucklerfamily.estate],
 "dateModified":"2026-10-30"}

How we apply it to Cedwyn

• Fits the graph work now in progress. Worker 348231ae builds per-section scatter JSON at build time. The same build step can write the CSV, the landing page and the JSON-LD for 2 to 4 sections, so it costs nothing extra. Raise it as a [CEDWYN] HubSpot proposal for the build owner rather than editing their files.
• Use temporalCoverage and spatialCoverage honestly: the catalogue's real first and last record dates, and the place name only, with no family addresses or holdings.
• Public text rules apply to the dataset descriptions too: neutral third person, never name the project lead, none of the banned words (write "not checked"), no outbound links (sameAs only to our own Zenodo DOI if one is made).
• Measure: Search Console Dataset report (valid items), Dataset Search presence, and referrals from datasetsearch.research.google.com in the Analytics Engine beacon. Keep it only if it shows up within 8 weeks; otherwise leave the markup in place (it costs nothing) and stop investing.
• Status: proposal. No GO is needed for markup on our own site, but the licence choice should be logged in the HubSpot task body with its reasoning.

Sources

• developers.google.com (read)
• arxiv.org (Benjelloun, Chen, Noy 2020, read)
• research.google (Sostek et al. 2024, abstract read)
• blog.google (launch, 25M; snippet)

Raw Markdown: dataset-structured-data-google-dataset-search-evidence-catalogue.md · version and changes: changelog · machine index: agents.json