Wikidata:WikiProject Data Quality

Ensuring data quality is of utmost importance, as the goal of Wikidata is to “give more people more access to knowledge” and therefore, the data needs to fit the needs of the data consumers. The Wikidata community has already developed methods and tools that monitor relative completeness (e.g., Recoin gadget), encourage link validation and correction (e.g. Mix’N’Match) and help editors observe recent changes and identify vandalism. Moreover, the community started global discussions about relevant dimensions of data quality in a recent RFC that used a survey of Linked Data Quality methods as the debate’s starting point to better describe and categorize quality issues and add more quality aspects/dimensions, with the goal of developing a data quality framework for Wikidata (RfC:DataQualityFramework).

Motivated by this, on January 18, 2019, we organized a workshop on "Data Quality Management in Wikidata" which took place at Wikimedia Germany.

In this workshop, we discussed existing challenges of data quality in Wikidata and derived possible solutions for data quality monitoring and data quality assurance in the context of Wikidata.

The following query uses these:

• Items: human (Q5)     

• Properties: instance of (P31)     

  SELECT ?item ?label WHERE{
    ?item wdt:P31 wd:Q5 .
    ?item rdfs:label ?label FILTER(lang(?label) = 'en') .
    ?item skos:altLabel ?alias FILTER (LANG (?alias) = 'en')
    FILTER(?label = ?alias)
  } LIMIT 100
  

The following query uses these:

• Items: scholarly article (Q13442814)     

• Properties: instance of (P31)     

  #Labels containing markup tags
  
  SELECT DISTINCT ?item ?label
  WHERE
  {
    ?item wdt:P31 wd:Q13442814;
          rdfs:label ?label.
    FILTER CONTAINS(?label, "</").
  }
  LIMIT 100
  

The following query uses these:

• Items: scholarly article (Q13442814)     

• Properties: instance of (P31)     , title (P1476)     

  SELECT ?item ?title
  WHERE
  {
    ?item wdt:P31 wd:Q13442814;
          wdt:P1476 ?title .
    FILTER CONTAINS(?title, "&amp").
  }
  LIMIT 100
  

PubMed uses brackets to indicate that the original title is translated to English

The following query uses these:

• Items: scholarly article (Q13442814)     

• Properties: instance of (P31)     , PubMed publication ID (P698)     

  SELECT ?paper ?paperLabel ?pmid WHERE {
      ?paper wdt:P31 wd:Q13442814;
             wdt:P698 ?pmid;
             rdfs:label ?paperLabel
      FILTER(lang(?paperLabel)="en")
      FILTER(STRSTARTS(?paperLabel, "[")).
      FILTER(STRENDS(?paperLabel, "]")).
  } LIMIT 100
  

https://www.nlm.nih.gov/bsd/licensee/elements_descriptions.html#articletitle explains the brackets, and that titles may include other non-title words:

• Non-EN title that is not yet translated will be just: [In Process Citation]
• Explanatory information is enclosed in parentheses, eg: (author's transl)
• Corporate/collective authors may appear at the end, eg: GISU. Interdisciplinary Group for the Study of Ulcer.
• OLDMEDLINE subset (<CitationSubset> = OM) may have: Not Available

https://www.nlm.nih.gov/bsd/licensee/elements_descriptions.html#verniculartitle: <VernacularTitle> hold the original, untranslated title.

• Non-Roman alphabet language titles are transliterated to Latin
• https://www.nlm.nih.gov/bsd/licensee/elements_descriptions.html#language: <Language> holds the lang of the article (thus of the original title), as ISO 3-letter code

• Overview of Data Quality Tools on Wikidata (2019-01-18) - presentation by Lydia Pintscher and Lucas Werkmeister at Workshop on Data Quality Management in Wikidata.
  • Primary sources tool - WD:PST
  • Recoin - Relative Completeness Indicator - WD:Recoin

See Scholia on data quality for publications. Please add missing publications to Wikidata as publication items and add main subject (P921): data quality (Q1757694) for the items to be included in this list.

• Workshop on Data Quality Management in Wikidata (Q59426297)

These should be searched weekly.

• Wikidata:Database reports/items with P569 greater than P570 People who died before they were born.
• Wikidata:Database reports/unmarked supercentenarians People over 120 years old.
• Wikidata:Database_reports/identical_birth_and_death_dates Doppelgangers with same birth and death dates
• Wikidata:WikiProject Names/lists/people with a given name identical to their family name People with mixed up given name and surname, usually Hungarians and Asian people where the family name comes first

These are for the external sources to monitor errors we have found.

• Wikidata:WikiProject Authority control/VIAF errors
• Wikidata:WikiProject Authority control/The Peerage errors
• Wikidata:WikiProject Authority control/LCCN errors
• Wikidata:WikiProject Authority control/Archivio Storico Ricordi errors (this resource is full of uncorrected typos)

• Wikidata:WikiProject Conflation
• Wikidata:WikiProject Duplicates
• Wikidata:WikiProject Deprecate P642

Events

• Wikidata:Events/Data Quality Days 2022
• Wikidata:Events/Data Quality Days 2021

The participants listed below can be notified using the following template in discussions:
{{Ping project|Data Quality}}

• Wikidata:WikiProject Virtual Twins — can be seen as a data quality project, since a pair of twins is mostly due to random and to the biases that exist in Wikidata coverage