Second i2b2 Shared-Task and Workshop, 2008.
Obesity Challenge (A Shared-Task on Obesity): Who's obese and what co-morbidities do they (definitely/likely) have?

Third i2b2 Shared-Task and Workshop, 2009.
Medication Extraction Challenge

Fourth i2b2 Shared-Task and Workshop, 2010.
Relations Challenge

Fifth i2b2 Shared-Task and Workshop, 2011.
Coreference Challenge

Sixth i2b2 Shared-Task and Workshop, 2012.
Temporal Relations Challenge

Seventh i2b2 Shared-Task and Workshop, 2014.
Heart Disease Challenge