Bolderdash and Wikipedia think. When you think Wikipedia has quality, and it has, it does not have absolute quality. I have added a lot of information from Wikipedia to Wikidata and there is a lot that is plain wrong from a data perspective, there are the errors and there is a lot that is just missing. This is particularly true when the subject is not really what people are interested in. Things like the Polk award, subdistricts of Botswana the list is long. I am adding much of the information by hand, add missing parts and the main use for the missing data is in the relations.

As I have said so often, quality of data is in having the same data in multiple sources. It follows that the data that can safely be added to Wikidata is the data where multiple sources agree on the represented facts. This is done easiest by bots and indeed there algorithms are defined in their code. When new data is included based on a multitude of sources, what is the source? Particularly when data is inconsistent as multiple sources cannot agree on specific data, sources become relevant but it is also where you go into real research.

Arguably, when data sources differ, you easily get into disputed facts and fake facts. This is where sourcing the facts becomes relevant. It is also where you get into real research and where as a consequence the license of the information becomes irrelevant.

In my opinion, we have grown up thinking in serial sourcing and particularly when you apply this approach on data stores like Wikidata your algorithms and thinking fails reality.

On 7 July 2018 at 19:55, Stas Malyshev <smalyshev@wikimedia.org> wrote:

> I agree this is misconception that a copyright license make any direct
> change to data reliability. But attribution requirement does somewhat
> indirectly have an impact on it, as it legally enforce traceability.

While true, I don't think it's of much practical use if traceability is
what you are seriously interested in. Imagine Wikidata were CC-BY, so
each piece of data you use from Wikidata now has to be marked as "coming
from Wikidata.Org". What have you gained? Wikidata is huge, and this
mark doesn't even tell you which item it is from, while being completely
satisfactory legally. Even more useless it is for actually ensuring the
data is correct or tracing its provenance to primary sources - you'd
still have to find the item and check the references manually (or
automatically, maybe) as you could do for CC0. CC-BY license would not
have added very much on Wikidata side.
All this is while, of course, even with CC0 nothing prevents you from
importing Wikidata data in such a way that each piece of data still
carries the mark "coming from Wikidata". While it is not a legal
requirement with CC0, nothing in CC0 prevents that from happening. If
your provenance needs are matched by this, there's nothing preventing
you from doing this, and legal requirements of CC-BY do not improve it
for you in any way - they just would force people that *do not* need to
do it still do it.

> That is I strongly disagree with the following assertion: "a license
> that requires BY sucks so hard for data [because] attribution
> requirements grow very quickly". To my mind it is equivalent to say that

I think this assertion (that attribution requirements grow) is factually
true. Each data piece from CC-BY data set needs to carry attribution. If
your data needs require to combine several data sets, each of them needs
to carry attribution. This attribution should be carried through all
data processing pipelines. You may be OK with this growth, but as I just
explained above, these requirements, while being onerous for people that
don't need tracing each piece of data, are still unsatisfactory in many
cases for those that do. So having CC-BY would be both onerous and useless.

> we will throw away traceability because it is subjectively judged too
> large a burden, without providing any start of evidence that it indeed
> can't be managed, at least with Wikimedia current ressources.

It's not Wikimedia that will be shouldering the burden, it's every user
of Wikimedia data sets.

Stas Malyshev

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