Just published in BMJ Open is “A method for early evaluation of a recently introduced technology by deriving a comparative group from existing clinical data: a case study in external support of the Marfan aortic root” by Tom Treasure, Sonya Crowe, KM John Chan, Aaron Ranasinghe, Rizwan Attia, Belinda Lees, Martin Utley, Tal Golesworthy, and John Pepper. You can read the article on the BMJ Open website here.