Quality Indicator 1: Dates & Times
Datatype compatibility
Literal values for a given property must have datatypes that are
mutually compatible. Suppose a dataset contains the
dct:created
property. If all corresponding literals
have datatype IRI xsd:date
, or datatype IRIs that
can be cast to it (e.g., xsd:gYear
), then creation
dates can be uniformly filtered and aggregated over. However, if
only some literals have datatype IRI xsd:date
while
others have ― for example ― datatype IRI
xsd:string
, values cannot be uniformly filtered or
aggregated over.
Datatype overview: date of publication/manufacturing
The following pie charts give an overview of the datatype
compatibility for the properties
iisg:dateOfPublication
and
iisg:dateOfManufacturing
. They quantify the number of
literals for each datatype IRI. The Figure 1 shows the
results for the 2019 version of the IISG Knowledge Graph, while
Figure 2 shows the results for live current version.
Uninterpretable dates: date of publication
The Figure 3 shows the 100 most common string values for
the predicate iisg:dateOfPublication
. The diagram
shows that cleaning only the 10 most common strings will
significantly improve the data quality of this property.