---
title: "Wikidata: A Free Collaborative Knowledgebase (2014)"
description: "The authors describe Wikidata, a Wikimedia project launched in October 2012. 24 references, cited by 670 papers here."
authors: ["Denny Vrandečić", "Markus Krötzsch"]
year: 2014
venue: "Communications of the ACM 57(10)"
source: "https://iccl.inf.tu-dresden.de/web/Article4002/en"
licence: "All rights reserved — free to read at the source"
summary_licence: "Elamur Cosmic License"
canonical: "https://research.elamur.ai/free/en/papers/vrandecic-2014-wikidata-free-collaborative-knowledgebase/"
---
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# Wikidata: A Free Collaborative Knowledgebase

**Authors:** [Denny Vrandečić](https://md.research.elamur.ai/free/en/authors/denny-vrandecic/) and [Markus Krötzsch](https://md.research.elamur.ai/free/en/authors/markus-krotzsch/) · **Year:** 2014 · **Venue:** Communications of the ACM 57(10) · **Licence:** All rights reserved — free to read at the source

**Links:** [Publisher's page](https://iccl.inf.tu-dresden.de/web/Article4002/en) · [PDF](https://iccl.inf.tu-dresden.de/w/images/8/89/Wikidata-CACM-2014.pdf)

**Citations:** [670](https://md.research.elamur.ai/free/en/papers/vrandecic-2014-wikidata-free-collaborative-knowledgebase/cited-by/) in our library, of the 149,439 papers whose bibliographies we read

## Summary
Wikipedia has accumulated a large number of structured facts: numbers, dates, coordinates, and relations between entities. However, they are scattered across roughly 30 million articles in 287 language editions. Extracting them automatically is difficult, and values often differ from one article to another. The authors describe Wikidata, a Wikimedia project launched in October 2012. It became a single multilingual data repository for all Wikipedias and for third-party applications. The project rests on several principles. Both the data and its schema can be edited. Conflicting statements may be stored side by side. Facts are accompanied by references to primary sources. There is one site for all languages, and labels are translated separately. The data model is built on property–value pairs, where each property has a defined type. More complex statements can include additional context, such as a date, and a source. The first stage was the migration of interlanguage links, which immediately produced millions of items. In less than two years, Wikidata became one of the most active Wikimedia projects. The data are available in JSON and RDF formats under terms that restrict reuse as little as possible. This makes the resource useful both for research and for developing new services.

## Key points
- Launch stages: in January 2013, the Hungarian, Hebrew and Italian Wikipedias were the first to connect to Wikidata. English joined in February, and all editions were connected in March. At the same time, the Lua language was introduced, and scripts written in it can read data from Wikidata.
- The essence of the problem is illustrated with the example of Rome. Each of the 207 articles about the city contained a list of 206 links to other language versions, 42,642 lines in total. In 66 of the 287 editions, there was more interlanguage-link text than actual article content. Bots migrated more than 240 million such links from Wikipedia.
- Statistics as of August 2014: about 15.8 million items and 43.2 million statements, of which 23.2 million have a source. Also 52.8 million labels, 54,670 registered contributors, and more than 157 million edits. The most frequently used property is "instance of".
- There are only a few data types: a link to another item, string, quantity, date and time, geographic coordinates, URL, and media files. Labels, aliases and descriptions can be specified for 358 languages.
- The authors compare Wikidata with other projects. Semantic MediaWiki stores data within the page text, and OpenCyc cannot be edited by the public. Freebase ties data to rigid types and runs on proprietary software. DBpedia and Yago merely extract data from Wikipedia and do not store information about sources.

*Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.*

📚 Shelves (2): [🖥️ Computer Science](https://md.research.elamur.ai/free/en/shelves/computer-science/) · 16,667 works · [🤖 Artificial Intelligence](https://md.research.elamur.ai/free/en/shelves/computer-science/artificial-intelligence/) · 16,194 works

🧭 Topics (1): [🕸️ Knowledge graphs & ontologies](https://md.research.elamur.ai/free/en/topics/knowledge-graphs/) · 192 works

💡 Concepts (2): [💡 Natural language processing](https://md.research.elamur.ai/free/en/concepts/natural-language-processing/) · 131 works · [💡 Knowledge graph](https://md.research.elamur.ai/free/en/concepts/knowledge-graph/) · 49 works

## Cite

Cite as: Denny Vrandečić and Markus Krötzsch. 2014. Wikidata: A Free Collaborative Knowledgebase. Communications of the ACM 57(10).

The paper itself, not this page. BibTeX from the library's record of the work.

```bibtex
@inproceedings{vrandecic2014wikidata,
  title = {{Wikidata: A Free Collaborative Knowledgebase}},
  author = {Denny Vrandečić and Markus Krötzsch},
  booktitle = {Communications of the ACM 57(10)},
  year = {2014},
  url = {https://iccl.inf.tu-dresden.de/web/Article4002/en}
}
```

- [← previous Fast and Robust Neural Network Joint Models for Statistical Machine Translation](https://md.research.elamur.ai/free/en/papers/devlin-2014-fast-robust-neural-network-joint/)
- [next → Incremental Joint Extraction of Entity Mentions and Relations](https://md.research.elamur.ai/free/en/papers/li-2014-incremental-joint-extraction-entity-mentions/)
- [↑ back to papers of 2014](https://md.research.elamur.ai/free/en/papers/2014/)

## References

24 references, 0 of them with a card of ours. ↗ leads to the work, «find» searches for one we have no id for yet.

1. Ayers, P., Matthews, C., and Yates, B. How Wikipedia Works: And How You Can Be a Part of It. No Starch Press, San Francisco, CA, 2008. [find](https://scholar.google.com/scholar?q=Ayers%2C+P%2E%2C+Matthews%2C+C%2E%2C+and+Yates%2C+B%2E+How+Wikipedia+Works%3A+And+How+You+Can+Be+a+Part+of+It%2E+No+Starch+Press%2C+San+Francisco%2C+CA%2C+2008%2E)
2. Barrett, D.J. MediaWiki. O’Reilly Media, Inc., Sebastopol, CA, 2008. [find](https://scholar.google.com/scholar?q=Barrett%2C+D%2EJ%2E+MediaWiki%2E+O%E2%80%99Reilly+Media%2C+Inc%2E%2C+Sebastopol%2C+CA%2C+2008%2E)
3. Bennett, R., Hengel-Dittrich, C., O’Neill, E.T., and Tillett, B.B. VIAF (Virtual International Authority File): Linking Die Deutsche Bibliothek and Library of Congress name authority files. In Proceedings of the World Library and Information Congress 72 nd General Conference and Council (Seoul, Sout… [find](https://scholar.google.com/scholar?q=Bennett%2C+R%2E%2C+Hengel%2DDittrich%2C+C%2E%2C+O%E2%80%99Neill%2C+E%2ET%2E%2C+and+Tillett%2C+B%2EB%2E+VIAF+%28Virtual+International+Authority+File%29%3A+Linking+Die+Deutsche+Bibliothek+and+Library+of+Congress+name+authority+files%2E+In+Proceed)
4. Berners-Lee, T., Hendler, J., and Lassila, O. The Semantic Web. Scientific American (May 2001), 96–101. [find](https://scholar.google.com/scholar?q=Berners%2DLee%2C+T%2E%2C+Hendler%2C+J%2E%2C+and+Lassila%2C+O%2E+The+Semantic+Web%2E+Scientific+American+%28May+2001%29%2C+96%E2%80%93101%2E)
5. Bizer, C., Heath, T., and Berners-Lee, T. Linked data: The story so far. International Journal on Semantic Web and Information Systems 5, 3 (2009), 1–22. [find](https://scholar.google.com/scholar?q=Bizer%2C+C%2E%2C+Heath%2C+T%2E%2C+and+Berners%2DLee%2C+T%2E+Linked+data%3A+The+story+so+far%2E+International+Journal+on+Semantic+Web+and+Information+Systems+5%2C+3+%282009%29%2C+1%E2%80%9322%2E)
6. Bizer, C., Lehmann, J., Kobilarov, G., Auer, S., Becker, C., Cyganiak, R., and Hellmann, S. DBpedia: A crystallization point for the Web of Data. Journal of Web Semantics 7, 3 (Sept. 2009), 154–165. [find](https://scholar.google.com/scholar?q=Bizer%2C+C%2E%2C+Lehmann%2C+J%2E%2C+Kobilarov%2C+G%2E%2C+Auer%2C+S%2E%2C+Becker%2C+C%2E%2C+Cyganiak%2C+R%2E%2C+and+Hellmann%2C+S%2E+DBpedia%3A+A+crystallization+point+for+the+Web+of+Data%2E+Journal+of+Web+Semantics+7%2C+3+%28Sept%2E+2009%29%2C+154%E2%80%93165%2E)
7. Bollacker, K., Evans, C., Paritosh, P., Sturge, T., and Taylor, J. Freebase: A collaboratively created graph database for structuring human knowledge. In Proceedings of the ACM SIGMOD International Conference on Management of Data (Vancouver, BC, Canada, June 9–12). ACM Press, New York, 2008, 1247–1… [find](https://scholar.google.com/scholar?q=Bollacker%2C+K%2E%2C+Evans%2C+C%2E%2C+Paritosh%2C+P%2E%2C+Sturge%2C+T%2E%2C+and+Taylor%2C+J%2E+Freebase%3A+A+collaboratively+created+graph+database+for+structuring+human+knowledge%2E+In+Proceedings+of+the+ACM+SIGMOD+International+Co)
8. Buneman, P., Cheney, J., Tan, W.-C., and Vansummeren, S. Curated databases. In Proceedings of the 27 th Symposium on Principles of Database Systems, M. Lenzerini and D. Lembo, Eds. (Vancouver, BC, Canada, June 9–12). ACM Press, New York, 2008, 1–12. [find](https://scholar.google.com/scholar?q=Buneman%2C+P%2E%2C+Cheney%2C+J%2E%2C+Tan%2C+W%2E%2DC%2E%2C+and+Vansummeren%2C+S%2E+Curated+databases%2E+In+Proceedings+of+the+27+th+Symposium+on+Principles+of+Database+Systems%2C+M%2E+Lenzerini+and+D%2E+Lembo%2C+Eds%2E+%28Vancouver%2C+BC%2C+Can)
9. Erxleben, F., Günther, M., Krötzsch, M., Mendez, J., and Vrandečić, D. Introducing Wikidata to the Linked Data Web. In Proceedings of the 13 th International Semantic Web Conference (Trentino, Italy, Oct. 19–23). Springer, Berlin, 2014. [find](https://scholar.google.com/scholar?q=Erxleben%2C+F%2E%2C+G%C3%BCnther%2C+M%2E%2C+Kr%C3%B6tzsch%2C+M%2E%2C+Mendez%2C+J%2E%2C+and+Vrandec%CC%8Cic%CC%81%2C+D%2E+Introducing+Wikidata+to+the+Linked+Data+Web%2E+In+Proceedings+of+the+13+th+International+Semantic+Web+Conference+%28Trentino%2C+Italy)
10. Ferrucci, D.A., Brown, E.W., Chu-Carroll, J., Fan, J., Gondek, D., Kalyanpur, A., Lally, A., Murdock, J.W., Nyberg, E., Prager, J.M., Schlaefer, N., and Welty, C.A. Building Watson: An overview of the DeepQA project. AI Magazine 31, 3 (Fall 2010), 59–79. [find](https://scholar.google.com/scholar?q=Ferrucci%2C+D%2EA%2E%2C+Brown%2C+E%2EW%2E%2C+Chu%2DCarroll%2C+J%2E%2C+Fan%2C+J%2E%2C+Gondek%2C+D%2E%2C+Kalyanpur%2C+A%2E%2C+Lally%2C+A%2E%2C+Murdock%2C+J%2EW%2E%2C+Nyberg%2C+E%2E%2C+Prager%2C+J%2EM%2E%2C+Schlaefer%2C+N%2E%2C+and+Welty%2C+C%2EA%2E+Building+Watson%3A+An+overview+of+the)
11. Guha, R.V., McCool, R., and Fikes, R. Contexts for the Semantic Web. In Proceedings of the Third International Semantic Web Conference, Vol. 3298 of LNCS, S.A. McIlraith, D. Plexousakis, and F. van Harmelen, Eds. (Hiroshima, Japan, Nov. 7–11). Springer, Berlin, 2004, 32–46. [find](https://scholar.google.com/scholar?q=Guha%2C+R%2EV%2E%2C+McCool%2C+R%2E%2C+and+Fikes%2C+R%2E+Contexts+for+the+Semantic+Web%2E+In+Proceedings+of+the+Third+International+Semantic+Web+Conference%2C+Vol%2E+3298+of+LNCS%2C+S%2EA%2E+McIlraith%2C+D%2E+Plexousakis%2C+and+F%2E+van+Ha)
12. Hale, S.A. Multilinguals and Wikipedia Editing. arXiv:1312.0976 [cs.CY], 2013; http://arxiv.org/abs/1312.0976 — [arXiv:1312.0976](https://arxiv.org/abs/1312.0976) [↗](http://arxiv.org/abs/1312.0976)
13. Hoffart, J., Suchanek, F.M., Berberich, K., and Weikum, G. YAGO2: A spatially and temporally enhanced knowledge base from Wikipedia. Artificial Intelligence (Special Issue on Artificial Intelligence, Wikipedia, and Semi-Structured Resources) 194 (Jan. 2013), 28–61. [find](https://scholar.google.com/scholar?q=Hoffart%2C+J%2E%2C+Suchanek%2C+F%2EM%2E%2C+Berberich%2C+K%2E%2C+and+Weikum%2C+G%2E+YAGO2%3A+A+spatially+and+temporally+enhanced+knowledge+base+from+Wikipedia%2E+Artificial+Intelligence+%28Special+Issue+on+Artificial+Intelligence%2C+)
14. Klein, M. and Kyrios, A. VIAFbot and the integration of library data on Wikipedia. code{4}lib Journal 22 (Oct. 2013); [http://journal.code4lib.org/articles/8964](http://journal.code4lib.org/articles/8964) [↗](http://journal.code4lib.org/articles/8964)
15. Krötzsch, M., Vrandečić, D., Völkel, M., Haller, H., and Studer, R. Semantic Wikipedia. Journal of Web Semantics 5, 4 (Dec. 2007), 251–261. [find](https://scholar.google.com/scholar?q=Kr%C3%B6tzsch%2C+M%2E%2C+Vrandec%CC%8Cic%CC%81%2C+D%2E%2C+V%C3%B6lkel%2C+M%2E%2C+Haller%2C+H%2E%2C+and+Studer%2C+R%2E+Semantic+Wikipedia%2E+Journal+of+Web+Semantics+5%2C+4+%28Dec%2E+2007%29%2C+251%E2%80%93261%2E)
16. Lenat, D.B. and Guha, R.V. Building Large Knowledge-Based Systems: Representation and Inference in the Cyc Project. Addison-Wesley, Boston, MA, 1989. [find](https://scholar.google.com/scholar?q=Lenat%2C+D%2EB%2E+and+Guha%2C+R%2EV%2E+Building+Large+Knowledge%2DBased+Systems%3A+Representation+and+Inference+in+the+Cyc+Project%2E+Addison%2DWesley%2C+Boston%2C+MA%2C+1989%2E)
17. Leuf, B. and Cunningham, W. The Wiki Way: Quick Collaboration on the Web. Addison-Wesley Professional, Boston, MA, 2001. [find](https://scholar.google.com/scholar?q=Leuf%2C+B%2E+and+Cunningham%2C+W%2E+The+Wiki+Way%3A+Quick+Collaboration+on+the+Web%2E+Addison%2DWesley+Professional%2C+Boston%2C+MA%2C+2001%2E)
18. MacGregor, R.M. Representing reified relations in Loom. Journal of Experimental and Theoretical Artificial Intelligence 5, 2–3 (1993), 179–183. [find](https://scholar.google.com/scholar?q=MacGregor%2C+R%2EM%2E+Representing+reified+relations+in+Loom%2E+Journal+of+Experimental+and+Theoretical+Artificial+Intelligence+5%2C+2%E2%80%933+%281993%29%2C+179%E2%80%93183%2E)
19. Moreau, L. The foundations for provenance on the Web. Foundations and Trends in Web Science 2, 2–3 (Oct. 2010), 99–241. [find](https://scholar.google.com/scholar?q=Moreau%2C+L%2E+The+foundations+for+provenance+on+the+Web%2E+Foundations+and+Trends+in+Web+Science+2%2C+2%E2%80%933+%28Oct%2E+2010%29%2C+99%E2%80%93241%2E)
20. Noy, N. and Rector, A., Eds. Defining N-ary Relations on the Semantic Web. W3C Working Group Note, Apr. 12, 2006; [http://www.w3.org/TR/swbp-n-aryRelations/](http://www.w3.org/TR/swbp-n-aryRelations/) [↗](http://www.w3.org/TR/swbp-n-aryRelations/)
21. Tunstall-Pedoe, W. True Knowledge: Open-domain question answering using structured knowledge and inference. AI Magazine 31, 3 (Fall 2010), 80–92. [find](https://scholar.google.com/scholar?q=Tunstall%2DPedoe%2C+W%2E+True+Knowledge%3A+Open%2Ddomain+question+answering+using+structured+knowledge+and+inference%2E+AI+Magazine+31%2C+3+%28Fall+2010%29%2C+80%E2%80%9392%2E)
22. Unxos GmbH. GeoNames (launched 2005); [http://www.geonames.org](http://www.geonames.org) [↗](http://www.geonames.org)
23. Vrandečić, D. The rise of Wikidata. IEEE Intelligent Systems 28, 4 (July/Aug. 2013), 90–95. [find](https://scholar.google.com/scholar?q=Vrandec%CC%8Cic%CC%81%2C+D%2E+The+rise+of+Wikidata%2E+IEEE+Intelligent+Systems+28%2C+4+%28July%2FAug%2E+2013%29%2C+90%E2%80%9395%2E)
24. Wolfram Research. Wolfram Alpha (launched 2009); [https://www.wolframalpha.com](https://www.wolframalpha.com) Denny Vrandečić (vrandecic@google.com) is an ontologist at Google, San Francisco, and was project director of Wikidata at Wikimedia Deutschland, Berlin, until September 2013. Markus Krötzsch (markus.kroetzsch@tu-dresden.… [↗](https://www.wolframalpha.com)

*Updated 1 November 2026*