Not sure what data sources they are using here but there is probably certain organisations which a lot of their stuff is missed and some where everything is present. If it's similar to Google scholar a lot of the stuff my uni does doesn't end up on there.

Fully agree that papers published has no correlation with an organisations actual overall contribution to the field. Even citations really, because in some cases something broad will get cited a lot as it relates to a lot of papers without actually presenting something new or important.