Ignacio Marín León, MD, PhD IBIS-CSIC-Rocio University Hospital, Seville, Spain: CIBERESP. ENEBRO Foundation, Spain Ignacio Marín a former associate professor of medicine at Seville University, and head of the Department of Internal Medicine at Valme University Hospital, Seville. He was awarded his medical degree in 1975 from the Universidad Autónoma of Madrid and received his PhD in 1987 from Complutense University of Madrid. From 1993 to 1994, he was a research fellow at the RAND Corporation–UCLA, Santa Monica, USA. Dr Marín’s main research interest is clinical effectiveness or how to measure, improve, and change professional practice. For the last 20 years he has focused on the development and implementation of guidelines. He has published a number of articles in peer-reviewed journals and is a member of the editorial board of Evidence Based Medicine (Spanish edition). Dr Marín is a project leader of several national projects and a researcher on European projects related to knowledge management in medicine and clinical practice guidelines. He iwas former chairman of the Spanish Research Network on Clinical Practice Guidelines (REDEGUÍAS), and the Latin-American Guidelines Network (Ibero-GIN), associated to GIN, from 1998-2016. He is a member of EFIM Guidelines working Group, since 2019.