Introduction

Authority files

Consistently refer to entities

• Via identifier ("things, not strings")
• GND, MeSH, STW, ISIL, RePEc Author ID…

Linking hubs

Connect identifiers among authority files

• owl:sameAs, skos:exactMatch, skos:closeMatch…
• VIAF, sameAs.org, Wikidata…

Wikidata

• Knowledge base of Wikimedia projects
• All kinds of entities
  • concepts, places, people, works…

Wikidata usage

• Editable by anyone
  • via Website and API
  • via apps that use the API
• Data available
  • http://query.wikidata.org/ (SPARQL)
  • JSON API & database dumps

Wikidata statements

Wikidata item example

Authority file identifiers in Wikidata

More than half of all Wikidata properties

• Datatype external identifier (~1,750)
• Properties for authority control (~1,500)
• Properties with corresponding KOS (~220)

Wikidata–-ISIL (organizations)

Example:

Neuschwanstein Castle (Q4152)
ISIL (P791): DE-MUS-051612

Current state:

• lobid.org: ~15,000 ISIL (DACH only)
• Wikidata: ~6,500 ISIL

Tool: Mix'n'match

• Web application mapping tool
• Helps to add 1-to-1-mappings

https://tools.wmflabs.org/mix-n-match/

Step 1: Upload ISIL list with names

Step 2: Confirm match candidates

GND–-RePEc Author ID

• In the EconBiz economics search portal authors are identified differently:
  • by GND ID in data from ZBW's Econis catalog
  • by RePEc Author ID in data from Research Papers for Economics
• Large volumes: 450,000 vs. 50,000 distinct persons
• ~3,000 pairs of IDs discovered in a previous project

Person identifiers in Wikidata and EconBiz

Utilizing Wikidata as linking hub

• Wikidata-Properties for both identifier systems

  • GND ID (P227): ~375,000 items which are humans
  • RePEc Short-ID (P2428): ~2,200 items

• Since every identifier should identify exactly one person, we can derive

  • GND ID ⟶ Wikidata ID ⟶ RePEc ID
  • RePEc ID ⟶ Wikidata ID ⟶ GND ID

  where both properties have values (~760 items, as of 2017-04-25)

Step 1: Supplement WD items with RePEc Author IDs

• 77 WD items with GND ID without RePEc Short-ID

• Transform to QuickStatements2 input file (SPARQL query, script)

• Copy & paste to QuickStatements2

Bulk editing with QuickStatements2

Further simplification with upcoming release of wdmapper command line tool

Step 2: Supplement WD items with GND IDs

• 384 WD items with RePEc Short-ID without GND ID
• same process as other direction

Step 3: Add "most important" authors with RePEc identifiers

• Scraped from ranking pages (Top 10% economists, Top 10% female economists)
• Transform and load into Mix'n'match (RePEc Top, RePEc Top Female)
• Same process as ISIL use case
  • Confirm match candidates (~ 1,600 of 4,600)

Step 4: Add "most important" authors with GND identifiers

• 18,000 GND authors with >30 publications in EconBiz
• Transform and load into Mix'n'match (GND economists (de))
• 25% matched automatically with Wikidata items
  • Confirm match candidates (~ 1500)

Step 5: Rinse and repeat

• Repeat Mix'n'match "sync" operation before starting to work manually
  • often, people are adding data at fast rate!
• Repeat bulk adding of missing identifiers to make use of complementing identifiers added meanwhile

Step 6: Add missing Wikidata items

• Verify missing authors indeed are not in Wikidata (step 3 and 4)
• Generate Wikidata item data from existing mappings (or lists, e.g., top female economists) in QuickStatements2 input format (SPARQL query, script)

Synthezised Wikidata items from ZBW's GND–RePEc mapping

2179 new Wikidata items created

• occupation "economist" from RePEc Author Service
• gender and date of birth/death (if available) from GND
• description from GND's info field and RePEc's "works for"

Recommendations for item creation

• Explain your plan and ask for feedback in the Wikidata project chat
• Pay attention to Wikidata's notability criteria
• Apply for a bot account to make mass edits (example)
• Use QuickStatements2 (more convenient input format, batch mode, sources)
• Source every statement ([hints](https://www.wikidata.org/w/index.php?title=Wikidata:Project_chat/Archive/2017/05#Source_statements_for_items_synte

d_from_authorities_-_recommendations.3F))

Result: the mapping in Wikidata

• 4087 matching GND - RePEc author IDs
  • 3081 matches from ZBW's mapping
  • 1006 matches contributed by Wikidata users
• 468 additional RePEc author IDs
• 52,444 additional GND IDs (present in EconBiz)

(as of 2017-06-04)

Top 10% RAS and frequent (>30) GND in EconBiz

Further results

• Mappings to other authorities for free (e.g., currently ~1550 RePEc ⟷ VIAF)
• Identifiers and items inserted by individual Wikidata contributors add up continuously
• Mapping steps can be repeated with additional data (e.g., top economists from Latin America)
• Further identifiers (VIAF, ORCID…) provide more opportunities for indirect matching

Results from every step in the mapping process and all indiviual efforts are immediately available

Tools

• Mix'n'match (system-supported intellectual matching)
• QuickStatements2 (addition of generated properties and items)
• wdmapper (harvest, diff & add mappings)
  • Support of indirect mappings (e.g., GND-WD-RePEc) in one step
  • Work in progress (no adding by now)
  • Daily harvested mappings in multiple formats:
    http://coli-conc.gbv.de/concordances/wikidata/

Tools for mass editing require approved bot account.

Limitations

• Mapping algorithms to find mapping candidates
• Limitation to easy-1-1-relationships
  • part-whole
  • often new Wikidata items required
  • depends on the use case
• Large sets of mappings and results
• Regular review required for maintainance

Benefits

• Outsourced interface, storage, and operation
• Crowdsourced mapping maintenance
• Wikidata has policies and tools for data quality
• Open Data for multiple and unknown uses
• Additional benefits:
  • multilingual Wikipedia links
  • lots of (formatted) data, nice pictures, …
  • links to multiple other vocabularies

Contact

Joachim Neubert
j.neubert@zbw.eu
http://zbw.eu/labs

Jakob Voss
jakob.voss@gbv.de
http://jakoblog.de/