Am 01.10.2015 um 18:40 schrieb Tom Morris:
On Thu, Oct 1, 2015 at 4:19 AM, Markus Krötzsch <markus@semantic-mediawiki.org> wrote:
On 01.10.2015 00:58, Ricordisamoa wrote:
I think Tom is referring to external identifiers such as MusicBrainz
 artist ID <https://www.wikidata.org/wiki/Property:P434> etc. and whether
Wikidata items should show all of them or 'preferred' ones only as we
did for VIAF redirects
 <https://www.wikidata.org/wiki/Wikidata:Requests_for_permissions/Bot/SamoaBot_38>.

Now if the external site reconciles the ids, we have these options:
(1) Keep everything as is (one main id marked as "preferred")
(2) Make the redirect ids deprecated on Wikidata (show people that we are aware of the ids but they should not be used)
(3) Delete the redirect ids

I think (2) would be cleanest, since it avoids that unaware users re-add the old ids. (3) would also be ok once the old id is no longer in circulation.

I agree #2 is best, although #1 could work too.  The problem with #3 is that an identifier, once minted, is never "no longer in circulation."  This is precisely why Wikidata items are never deleted.  There's always the possibility that someone will hold a reference to it somewhere.  Thad's use case isn't uncommon.

I think #2 is the only solution we should do. This is exactly what the deprecated rank is for: marking some information as valid for some point in time but telling the users that this should not be used any more.


Is there any benefit in removing old ids completely? I guess constraint reports will work better (but maybe constraint reports should not count deprecated statements in single value contraints ...).

The constraint reports definitely need to be fixed.  I recently saw a reference to a VIAF bot run that deleted a whole bunch of VIAF identifiers to "fix" things being flagged by some constraint.

Not sure if marking the statements as deprecated would already fix them. If not, the code creating these lists needs to be adjusted to ignore deprecated statements (maybe optionally?).

 
Other than this, I don't see a big reason to spend time on removing some ids. It's not wrong to claim that these are ids, just slightly redundant, and the old ids might still be useful for integrating with web sources that were not updated when the redirect happened.

Rather than not wasting time removing, I'd like to see affirmative statements that keeping them is a good thing.  If people find them annoying or cluttering, it's because of poor UI design, not because they lack usefulness.

Indeed and as far as I know the new ui will hide deprecated statements per default and only show them on demand by toggling.

Best regards
Bene