How many properties are created on Wikidata each month?

I was asked if there was a slowdown or even a stop in property creations on Wikidata.

The first idea was to make a SPARQL query on the Wikidata Query Service. A quick check shows that the date of creation of a property is not stored there, only the date of its last modification:

  wd:P31 ?property ?value .
  FILTER(DATATYPE(?value) = xsd:dateTime) .

There is of course a feature request for that (T151539), opened in 2016.

Wikidata relies on Mediawiki, the wiki software used by most projects of the Wikimedia Foundation. Each object (an item, a property or a lexeme) is stored as a page in Mediawiki. So let’s query its SQL database, using Quarry:

SELECT `date_creation`, COUNT(*) AS `count` FROM (
  SELECT MIN(SUBSTRING(`rev_timestamp`, 1, 6)) AS `date_creation`
  FROM `page`, `revision`
  WHERE `page`.`page_id` = `revision`.`rev_page`
  AND `page`.`page_namespace` = 120
  GROUP BY `page`.`page_title`
) `a`
GROUP BY `date_creation`
ORDER BY `date_creation` DESC

Properties are stored in a dedicated namespace, which id is 120 (line 5). For each page of a property, we retrieve the first date creation of its revisions (subquery). Then, we aggregate by month to get the number of properties created each month. Note that this method provides statistics only about properties that still exist.

Finally, we can make a graph:

Graph showing property creations on Wikidata by month

While it’s not as huge as in 2018, property creations is still active on Wikidata.