The use of "unknown" for the date of death in "probably dead persons" is pretty diffused. According to this query  it is used in 5861 humans. 
It would be interesting to know how many records would need to be updated (i.e. known date of birth, no date of death, age > 122 years), but I got a timeout.

FabC

Il giorno ven 20 set 2019 alle ore 17:59 Thomas Douillard <thomas.douillard@gmail.com> ha scritto:
We have also other properties on Wikidata to refine partial knowledge about the chronology of a life :
https://www.wikidata.org/wiki/Property:P1317 – floruit
https://www.wikidata.org/wiki/Property:P2032 / https://www.wikidata.org/wiki/Property:P2031 — floruit begin and end
that may overlap with https://www.wikidata.org/wiki/Property:P1319 https://www.wikidata.org/wiki/Property:P1326

I found myself sometimes using a century precision date for somebody we don’t really have information about the date of death but know it lived on some century.


Le ven. 20 sept. 2019 à 00:25, Olaf Simons <olaf.simons@pierre-marteau.com> a écrit :
On FactGrid we created two properties for this (maybe clever, maybe daft): P290 and P291 for estimates (or for knowledge) of an earliest and latest point in the life span. The necessity is here that we have loads of people with just a single data point like "studied in Jena in 1776" or "appeared on a list of voters in 1849". If that is all you know, you do actually know that the person is likely to have a birth date some 17 (or in the voters case at least 21) years before.

If a person is only once mentioned as retired that stretches the P290 date to some 60 years before and so on - you qualify the estimate accordingly.

I have no idea whether this is a good move on our site since we are not really that advanced in running the more intriguing SPARQL searches.

Olaf




> Fabrizio Carrai <fabrizio.carrai@gmail.com> hat am 19. September 2019 um 22:13 geschrieben:
>
>
> So, the question is if it would be fine and ethic to set the "Date of
> death" to "unknown" on the base of an old date of birth.
> And about the biography of living persons, I found this [1]
>
> Deceased persons, corporations, or groups of personsRecently dead or
> probably dead
> Anyone born within the past 115 years (on or after 19 September 1904) is
> covered by this policy unless a reliable source has confirmed their death.
> Generally, this policy does not apply to material concerning people who are
> confirmed dead by reliable sources. The only exception would be for people
> who have recently died, in which case the policy can extend for an
> indeterminate period beyond the date of death—six months, one year, two
> years at the outside. Such extensions would apply particularly to
> contentious or questionable material about the dead that has implications
> for their living relatives and friends, such as in the case of a possible
> suicide or a particularly gruesome crime. *Even absent confirmation of
> death, for the purposes of this policy anyone born more than 115 years ago
> is presumed dead* *unless* reliable sources confirm the person to have been
> living within the past two years. If the date of birth is unknown, editors
> should use reasonable judgement to infer—from dates of events noted in the
> article—if it is plausible that the person was born within the last 115
> years and is therefore covered by this policy.
>
> This would support the set of "Date of death" to "unknown" on the base of
> the "Date of birth". It remains hard to verify typo errors, but we are
> doing our best to verify the data of the several wikiprojects.
>
> The property set would become effective if done in mass by a bot or similar.
>
> By the way, I would extend be period to 122 years [2]
>
> FabC
>
> [1]
> https://en.wikipedia.org/wiki/Wikipedia:Biographies_of_living_persons#Deceased_persons,_corporations,_or_groups_of_persons
> [2] https://en.wikipedia.org/wiki/Oldest_people
>
> Il giorno gio 19 set 2019 alle ore 21:29 Andy Mabbett <
> andy@pigsonthewing.org.uk> ha scritto:
>
> > On Sat, 7 Sep 2019 at 07:53, Fabrizio Carrai <fabrizio.carrai@gmail.com>
> > wrote:
> >
> > > I found athletes with the "Date of born" but with NO "date of death".
> > > So a query on the age show me athletes up to 149 years old.
> > > Since the oldest know person was 122, what about to set "date of
> > > death = unknown value" for all the persons resulting older such age ?
> >
> > Yes, but check that the date of birth isn't a typo (i.e. 1875 instead
> > of 1975; or 1894 instead of 1984).
> >
> > Showing a living person as being dead would be a serious breach of the
> > BLP policy.
> >
> > --
> > Andy Mabbett
> > @pigsonthewing
> > http://pigsonthewing.org.uk
> >
> > _______________________________________________
> > Wikidata mailing list
> > Wikidata@lists.wikimedia.org
> > https://lists.wikimedia.org/mailman/listinfo/wikidata
> >
>
>
> --
> *Fabrizio*
> _______________________________________________
> Wikidata mailing list
> Wikidata@lists.wikimedia.org
> https://lists.wikimedia.org/mailman/listinfo/wikidata

Dr. Olaf Simons
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--
Fabrizio