[TalentSignal] citizenship requirement (and other JobPosting requirements)

Hello all, the extraordinarily observant among you may have noticed from 
the summary of progress in our first year 
<https://www.w3.org/community/talent-signal/2020/02/05/one-year-in/> 
that the following properties which we proposed to schema.org a couple 
of months ago were recently accepted into the January release:

  * physical requirement
  * security clearance requirement
  * sensory requirement
  * applicationContact,
  * employerOverview

Missing from that list is *citizenship requirement*. This is because 
Stuart Sutton raised a point 
<https://github.com/schemaorg/schemaorg/issues/2384#issuecomment-554768395> 
that I thought was worth bringing back here for further discussion:

    Phil, just a thought about "citizenship requirement". In the context
    of employment, I would think that the citizenship question goes to a
    candidate's legal work eligibility. Some of what HR Open Standards
    focuses on in this regard are: (a) eligibility types (e.g., "US
    noncitizen national", "alien authorized to work"; and (b)
    eligibility documentation (e.g., "permanent resident card", "US
    passport", "foreign passport with I-94/A form" etc.). Since a
    "citizenship requirement" might get to some of it, does it do the
    full trick?

We had proposed :

*|citizenshipRequirement|:*

    *Defintion:*Country of applicant's citizenship.
    *Expected Type:*Country, Text, Url

Would this be better:

*eligibilityToWorkRequirement: **Definition:* legal requirements such as 
citizenship, visa and other documentation required for an applicant to 
this job. *Expected Type:* Text
**

I know Text is a blunt instrument here, but I am not keen on trying to 
come up with a globally applicable vocabulary for this.

Are there many cases where citizenship is important if other criteria 
such as a work visa / green card are satisfied? Should we propose 
eligibilityToWorkRequirement /as well as/ citizenshipRequirement or 
/instead of/? (If we suggest both we need to be careful because it won't 
be clear whether they are alternatives or both required unless we alter 
the definition).

Phil

-- 

Phil Barker <http://people.pjjk.net/phil>. http://people.pjjk.net/phil
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