Help:Property constraints portal/Recency

complex constraint recency (Q102173107) specifies that the most recent value of a property on an item shouldn't be older than a given period of time. This is determined by the point in time (P585)-qualifier and the current date.

For example, the values for employees (P1128) are generally published once a year. Accordingly, one could define that the time period between today and the date used with P1128 shouldn't exceed 2 years.

It can be suitable for properties with quantity-datatype that have a required qualifier constraint for point in time (P585) and regularly get new values (e.g. once a year).

It is different from constraints for time-datatype properties: contemporary constraint, range constraint and the difference within range constraint.

Units for duration can be days, weeks, months, years. Calculation is done in days.

Given the infrastructure of Wikidata, it may not be desirable to store values more frequently than once a year. Accordingly, the time period would generally be minimum a year.

Contrary to standard property constraints, this constraint is added with has characteristic (P1552) on properties. As a complex constraint, it also requires the addition of {{Complex constraint}} to the property talk page.

The output is available only as a periodically updated report at Wikidata:Database reports/Complex constraint violations. It is limited to a specified number (generally 500 items). Consequently, it may not be suitable for population (P1082).

Note that the constraint wont check items that have some end date:

• dissolved, abolished or demolished date (P576)
• date of death (P570)
• date of official closure (P3999)
• end time (P582)

Possible actions

The report with the constraint violations allows to do a top-down analysis. It shows the gap between available data and an ideal situation.

• When querying and using data, one should bear in mind that gap.
• If suitable data is available, one could add recent values.
• If an item lacks an applicable end date, one could add that.

Also:

• It’s possible that the time period needs to be adjusted.

Parameters

This constraint has one mandatory and one optional parameter:

duration (P2047)

Contains maximum recency of data. It should have just one value. Units can be days, weeks, months, years. no value Help or unknown value Help are not permitted.

syntax clarification (P2916)

Contains a human-readable description. Can be specified several times in different languages.

Examples

Example 1

Values for employees (P1128) should be updated once per year, so the most recent values for shouldn't be older than 2 years.

employees	complex constraint recency edit duration 2 year 0 references add reference
		add value

Example 2

Values for students count (P2196) should be updated at least once per decade, so the values should generally not be older than 12 years.

students count	complex constraint recency edit duration 12 year 0 references add reference
		add value

Template

To define the constraint, {{Complex constraint}} with a sparql query needs to be added to the property's talk page.

This can be done by adding:
{{subst:Define recency constraint}}

Lists

• List properties with this constraint
• quantity-datatype properties with required point in time qualifier constraint

Statistics