Purya Baghaei is an associate professor in the English Department, Islamic Azad University, Mashhad Branch, Mashhad, Iran. He holds a PhD in applied linguistics from Alpen-Adria Universität, Klagenfurt, Austria. He is a scholar of the Alexander von Humboldt Foundation in Germany and has conducted postdoctoral research at universities in Vienna, Berlin, Dortmund, Jena, and Bamberg. His major research interest is in foreign language proficiency testing with a focus on the applications of item response theory models in test validation and scaling. He has widely published on educational measurement in leading international journals.