The membership program tier(s) an Offer (or a PriceSpecification, OfferShippingDetails, or MerchantReturnPolicy under an Offer) is valid for.

MemberProgram offered by an Organization, for example an eCommerce merchant or an airline.

Rating of a certification instance (as defined by an independent certification body). Typically this rating can be used to rate the level to which the requirements of the certification instance are fulfilled. See also [gs1:certificationValue](https://www.gs1.org/voc/certificationValue).

The [GS1 digital link](https://www.gs1.org/standards/gs1-digital-link) associated with the object. This URL should conform to the particular requirements of digital links. The link should only contain the Application Identifiers (AIs) that are relevant for the entity being annotated, for instance a [Product](https://schema.org/Product) or an [Organization](https://schema.org/Organization), and for the correct granularity. In particular, for products: - A Digital Link that contains a serial number (AI `21`) should only be present on instances of [IndividualProduct](https://schema.org/IndividualProduct) - A Digital Link that contains a lot number (AI `10`) should be annotated as [SomeProducts](https://schema.org/SomeProducts) if only products from that lot are sold, or [IndividualProduct](https://schema.org/IndividualProduct) if there is only a specific product. - A Digital Link that contains a global model number (AI `8013`) should be attached to a [Product](https://schema.org/Product) or a [ProductModel](https://schema.org/ProductModel). Other item types should be adapted similarly.

Indicates the current status of a certification: active or inactive. See also [gs1:certificationStatus](https://www.gs1.org/voc/certificationStatus).

Identifier of a certification instance (as registered with an independent certification body). Typically this identifier can be used to consult and verify the certification instance. See also [gs1:certificationIdentification](https://www.gs1.org/voc/certificationIdentification).

Date when a certification was last audited. See also [gs1:certificationAuditDate](https://www.gs1.org/voc/certificationAuditDate).

A color swatch image, visualizing the color of a [Product](https://schema.org/Product). Should match the textual description specified in the [color](https://schema.org/color) property. This can be a URL or a fully described ImageObject.

Certification information about a product, organization, service, place, or person.

A [National Provider Identifier](https://en.wikipedia.org/wiki/National_Provider_Identifier) (NPI) is a unique 10-digit identification number issued to health care providers in the United States by the Centers for Medicare and Medicaid Services.

A [MedicalOrganization](https://schema.org/MedicalOrganization) where the [IndividualPhysician](https://schema.org/IndividualPhysician) practices.

Indicates an IPTCDigitalSourceEnumeration code indicating the nature of the digital source(s) for some [CreativeWork](https://schema.org/CreativeWork).

The number of completed interactions for this entity, in a particular role (the 'agent'), in a particular action (indicated in the statistic), and in a particular context (i.e. interactionService).

The location of origin of the trip, prior to any destination(s).

The length of time an Observation took place over. The format follows `P[0-9]*[Y|M|D|h|m|s]`. For example, P1Y is Period 1 Year, P3M is Period 3 Months, P3h is Period 3 hours.

Represents the length and pace of a course, expressed as a [Schedule](https://schema.org/Schedule).

Indicates the kind of statistic represented by a [StatisticalVariable](https://schema.org/StatisticalVariable), e.g. mean, count etc. The value of statType is a property, either from within Schema.org (e.g. [median](https://schema.org/median), [marginOfError](https://schema.org/marginOfError), [maxValue](https://schema.org/maxValue), [minValue](https://schema.org/minValue)) or from other compatible (e.g. RDF) systems such as DataCommons.org or Wikidata.org.

The [observationAbout](https://schema.org/observationAbout) property identifies an entity, often a [Place](https://schema.org/Place), associated with an [Observation](https://schema.org/Observation).

Provides additional qualification to an observation. For example, a GDP observation measures the Nominal value.

Identifies the denominator variable when an observation represents a ratio or percentage.

Represents the length and pace of a course.

The total number of students that have enrolled in the history of the course.

Indicates (typically several) Syllabus entities that lay out what each section of the overall course will cover.

Indicates a property used as a constraint. For example, in the definition of a [StatisticalVariable](https://schema.org/StatisticalVariable). The value is a property, either from within Schema.org or from other compatible (e.g. RDF) systems such as DataCommons.org or Wikidata.org.