Our study of data quality was done per project: https://wikitech.wikimedia.org/wiki/Analytics/AQS/Wikistats_2/Data_Quality
We need to also do a data quality comparaytion adding "all-wikipedias" and understand differences with https://stats.wikimedia.org/EN/TablesWikipediaZZ.htm as numbers differ. Example: or 201505-01 druid has 10.4 M - Compared to 10.3 for WKS1