Javier Faulin is associate professor of statistics and operations research at the Public University of Navarra, Navarra, Spain. He is also a mentor and professor of operations research for the Spanish Open University (UNED), Madrid, Spain. Dr Faulin has been a visiting professor at the University of Sabana, Bogotá, Colombia, and the University of Montreal, Montreal, Canada, and a visiting scholar at the University of Cincinnati, Ohio, USA, and University College of Business, Dublin, Ireland. He also spent three years at the University of Surrey, Guildford, UK, as associate lecturer in decision making in business, and in 2007 and 2008 was a professeur invité at the Université de Rennes, Rennes, France. Angel A. Juan is an associate professor of simulation and data analysis at the Open University of Catalonia. He is also a lecturer of statistics at the Technical University of Catalonia. Dr Juan has also been a teacher of mathematics and statistics at Elian”s Boston School, Boston, USA; an assistant professor of mathematics at the University of Alicante, Alicante, Spain; a teacher of mathematics and computer science for the Catalan government”s Department of Education; assistant professor of applied statistics, simulation of computer networks and mathematics at the Open University of Catalonia, Barcelona, Spain; and a teacher of programming languages, computer networks and database management systems for the Catalan government”s Department of Education. Sebastián Martorell is associate professor in nuclear engineering and director of the Department of Chemical and Nuclear Engineering at the Universidad Politécnica de Valencia, from which he also received his MSc and Ph D. Dr Martorell is vice-chairman of the European Safety and Reliability Association (ESRA). He is also a member of the editorial board of the European Journal of Industrial Engineering. Jose Emmanuel Ramirez-Marquez is assistantprofessor at the Stevens Institute of Technology, Hoboken, USA. He is also director of the Quality Control and Reliability Engineering Division Board for the Institute of Industrial Engineers. Prior to receiving his Ph D in 2004, Dr Ramirez-Marquez was an area officer for the Secretaria de Hacienda y Credito Publico Servicio de Administracion Tributaria, Ciudad de Mexico, Mexico, and a graduate assistant at Rutgers, New Brunswick, USA.