Re: Do property values include lists of those value Types?

ItemList is intended to express an explicit ordering. If a specific
ordering is not required then simply providing the objects without being
wrapped in an ItemList (with ListItems) is sufficient and less verbose. For
example, there is no explicit order in a set of MemberProgramTiers, so
there is no need to wrap them in an ItemList.

There is no implicit characteristic that properties can also be lists of
the property. When an explicit order could be relevant (through ItemList)
it is made explicit in the schema, for example
https://schema.org/positiveNotes.

Hope that helps!

Alex.



On Thu, Oct 23, 2025 at 4:08 PM Zyle Moore <moore.zyle@gmail.com> wrote:

> Hey, hoping this is a quick question that I've just overlooked on the
> website.
>
> There is a specific type, ItemList, made up of ListItems, used to
> represent multiple values. But there are also some properties that would
> seem to be appropriate for lists of items, but do not say that ItemLists
> are valid values. For example, the MemberProgram type has a hasTiers
> property, with values expected to be MemberProgramTier. The property
> description states that it is "The tiers of a member program.", but it
> does not say that a value can be an ItemList.
>
> Is there some implicit characteristic, that all properties can also be
> lists of that property type? Would it be appropriate for the value to be
> an ItemList of MemberProgramTier? With HTML markup, I can just mention
> the property again, but for other non-markup representations, like a
> JSON object, what's the most appropriate way to convey this? Could all
> properties be represented as singular and plural, like Thing::name, or
> Person::givenName?
>
>
>
>