Agreed. In Mix'n'match, 145 out of 177catalogs have at least one instance of two or more external IDs matched to a single Wikidata item. External datasets, even curated ones, are messy.
Maybe the criterion should be "intended to be unique", or somesuch. On Sun, Mar 6, 2016 at 9:18 AM Markus Krötzsch < [email protected]> wrote: > Another reason why "uniqueness" is not such a good criterion: it cannot > be applied to decide the type of a newly created property (no > statements, no uniqueness score). In general, the fewer statements there > are for a property, the more likely they are to be unique. The criterion > rewards data incompleteness (example: if Luca deletes the six multiple > ids he mentioned, then the property could be converted -- and he could > later add the statements again). If you think about it, it does not seem > like a very good idea to make the datatype of a property depend on its > current usage in Wikidata. > > Markus > > On 05.03.2016 17:15, Markus Krötzsch wrote: > > Hi, > > > > I agree with Egon that the uniqueness requirement is rather weird. What > > it means is that a thing is only considered an "identifier" if it points > > to a database that uses a similar granularity for modelling the world as > > Wikidata. If the external database is more fine-grained than Wikidata > > (several ids for one item), then it is not a valid "identifier", > > according to the uniqueness idea. I wonder what good this may do. In > > particular, anybody who cares about uniqueness can easily determine it > > from the data without any property type that says this. > > > > Markus > > > > > > On 05.03.2016 15:35, Egon Willighagen wrote: > >> On Sat, Mar 5, 2016 at 3:25 PM, Lydia Pintscher > >> <[email protected]> wrote: > >>> On Sat, Mar 5, 2016 at 3:17 PM Egon Willighagen > >>> <[email protected]> > >>>> What is the exact process? Do you just plan to wait longer to see if > >>>> anyone supports/contradicts my tagging? Should I get other Wikidata > >>>> users and contributors to back up my suggestion? > >>> > >>> Add them to the list Katie linked if you think they should be > >>> converted. We > >>> wait a bit to see if anyone disagrees and I also do a quick sanity > >>> check for > >>> each property myself before conversion. > >> > >> I am adding comments for now. I am also looking at the comments for > >> what it takes to be "identifier": > >> > >> > https://www.wikidata.org/wiki/User:Addshore/Identifiers#Characteristics_of_external_identifiers > >> > >> > >> What is the resolution in these? There are some strong, often > >> contradiction, opinions... > >> > >> For example, the uniqueness requirement is interesting... if an > >> identifier must be unique for a single Wikidata entry, this is > >> effectively disqualifying most identifiers used in the life > >> sciences... simply because Wikidata rarely has the exact same concept > >> in Wikidata as it has in the remote database. > >> > >> I'm sure we can give examples from any life science field, but > >> consider a gene: the concept of a gene in Wikidata is not like a gene > >> sequence in a DNA sequence database. Hence, an identifier from that > >> database could not be linked as "identifier" to that Wikidata entry. > >> > >> Same for most identifiers for small organic compounds (like drugs, > >> metabolites, etc). I already commented on CAS (P231) and InChI (P234), > >> both are used as identifier, but none are unique to concepts used as > >> "types" in Wikidata. The CAS for formaldehyde and formaline is > >> identical. The InChI may be unique, but only of you strongly type the > >> definition of a chemical graph instead of a substance (as is now)... > >> etc. > >> > >> So, in order to make a decision which chemical identifiers should be > >> marked as "identifier" type depends on resolution of those required > >> characteristics... > >> > >> Can you please inform me about the state of those characteristics > >> (accepted or declined)? > >> > >> Egon > >> > >>> Cheers > >>> Lydia > >>> -- > >>> Lydia Pintscher - http://about.me/lydia.pintscher > >>> Product Manager for Wikidata > >>> > >>> Wikimedia Deutschland e.V. > >>> Tempelhofer Ufer 23-24 > >>> 10963 Berlin > >>> www.wikimedia.de > >>> > >>> Wikimedia Deutschland - Gesellschaft zur Förderung Freien Wissens e. V. > >>> > >>> Eingetragen im Vereinsregister des Amtsgerichts Berlin-Charlottenburg > >>> unter > >>> der Nummer 23855 Nz. Als gemeinnützig anerkannt durch das Finanzamt für > >>> Körperschaften I Berlin, Steuernummer 27/029/42207. > >>> > >>> _______________________________________________ > >>> Wikidata mailing list > >>> [email protected] > >>> https://lists.wikimedia.org/mailman/listinfo/wikidata > >>> > >> > >> > >> > > > > > _______________________________________________ > Wikidata mailing list > [email protected] > https://lists.wikimedia.org/mailman/listinfo/wikidata >
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