Inside University of Cologne's largest research partnership: Heinrich Heine University Düsseldorf

Behind University of Cologne's research output sits a defining relationship: 2,373 co-authored works with Heinrich Heine University Düsseldorf (Germany) in the five years to 2025, the university's single largest collaboration.

It anchors an unusually connected research base: 1,081 collaborating institutions across 80 countries, producing 35,490 joint works over the window, with international co-authors on 44% of output.

The collaborative work travels: its field-weighted citation impact stands at 3.0, where the world average is 1.0.

The Research Collaboration Index, the first global account of how universities actually collaborate, publishes its first full edition on Tuesday 15 September at 09:00 UK.

Every figure derives from the open global research record and is checkable at source.