Essex's alumni include two Nobel laureates, making the university one of only three non-Russell Group universities which have an alumni including a Nobel laureate, alongside the University of Greenwich and the London School of Hygiene & Tropical Medicine. The 1987 Nobel Peace Prize was awarded to Óscar Arias who completed his doctorate in Political Science in 1973. The 2010 Nobel Prize for Economics was awarded to Christopher Pissarides who gained his BA and MA degrees in Economics in the early 1970s. In 2016 former Essex academic Oliver Hart won the Nobel Prize for Economics. Derek Walcott, who received the 1992 Nobel Prize in Literature, served as Professor of Poetry at the university from 2010 to 2013 before his retirement.