use isAccessibleForFree on all Event classes [+CreativeWork] #900

richard-verhoeven opened this Issue Nov 18, 2015 · 11 comments


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Is there any particular reason why the property isAccessibleForFree is used on the class PublicationEvent only? It seems to me that this is a reasonable and (if true) important property for any kind of event, so I would strongly suggest to move it to Event.

danbri commented Nov 23, 2015

Thanks. This seems to be a case of something being added for one purpose with insufficient attention to its wider use. It was added for

Generalising seems worthwhile, although you soon run into numerous subtleties (geo restrictions, free-if-you-register etc., in case of content rather than events) that are too complex for to feasibly handle. But yes we should look at applying it to other event types at least, although the current definition "A flag to signal that the publication is accessible for free." really seems more concerned with creative works than events.


Regarding events, perhaps the definition could simply be changed to "A flag to signal that it is possible to attend the event for free."

Trying a systematic approach, isAccessibleForFree might make sense and be useful wherever the offer property is available, even though the textual definition might not be the same for each class. Indeed, isAccessibleForFree is bascially a shorthand for a particular kind of Offer. The latter remains available to express the mentioned subtleties.


The concept of access rights is applicable to other kinds of creative work as well.

E.g. CEDS defines a controlled vocabulary for Learning Resources with these options:

  • Free Access
  • Free Access with Registration
  • Limited Free Access
  • Available for Purchase
  • Available by Subscription
  • Publisher Defined



PublicationEvent is odd in that it uses a different meaning of "event" than the other Event types. PublicationEvent is for when a CreativeWork becomes available for consumption. The other Event types are for planned public or social occasions.

I would argue we are better off moving PublicationEvent out from under Event and expand the ranges of properties like startDate and endDate as necessary.

darobin commented Mar 30, 2016

Without getting into the many issues related to access management, we would really like to use isAccessibleForFree on CreativeWork. We have scholarly content that is Open Access (which means really to everyone) and content that isn't. It would make a lot of sense to use that property on the former, distinguishing those article from those where you get a page that's truncated after the abstract.

danbri commented Jul 25, 2016

+1 for broadening it to CreativeWork; it will be useful for Course too.

danbri commented Jul 25, 2016

and to Event for

btw @vholland - I agree there is a difference between emphasis of PublicationEvent and the other event subtypes. But both need to work both for forward-looking descriptions (potential events) and for historical logs of events actually having happened. Much as with Action, which serves a role for potential actions and for recording chains of activities that actually happened.

@danbri danbri changed the title from use isAccessibleForFree on all Event classes to use isAccessibleForFree on all Event classes [+CreativeWork] Jul 25, 2016

+1 for broadening as described.

@danbri danbri pushed a commit that closed this issue Jul 25, 2016
Dan Brickley Broadened isAccessibleForFree to be expected on events and creative w…

Fixes #900
@danbri danbri closed this in d793868 Jul 25, 2016
@danbri danbri pushed a commit that referenced this issue Jul 25, 2016
Dan Brickley Fixed RDFS bad edit: changes previously applied to older property 'fr…

Fixes (again) #900

@danbri would be better if the definition didn't mention publication

danbri commented Aug 10, 2016

Good point @RichardWallis!

Ok, "A flag to signal that the publication is accessible for free."
-> "A flag to signal that the publication or event is accessible for free."

Filed as #1290, since I don't like the same issue appearing twice in /docs/releases.html

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