 He earned his Doctor of Civil Law degree from the University of Santo Tomas, "summa cum laude" and was the class valedictorian.On December 22, 2011, Marites Dañguilan Vitug of online journalism site "Rappler.com", published an article alleging that the University of Santo Tomas (UST) "may have broken its rules" in granting Corona a doctorate in civil law and qualifying him for honors.She wrote that Corona did not submit a dissertation to complete his PhD as required by the university and that Corona overstayed, since UST requires that PhD programs be completed in five years with maximum residency of seven years.