What is Johannes de Villiers Graaff?
{{Infobox scientist <!-- Image --> | image = Johannes de Villiers Graaff.jpg | caption = <!-- Information --> | name = Johannes de Villiers Graaff | birth_date = {{birth date|1928|02|19|df=y}} | birth_place = [[Cape Town]], [[Union of South Africa]] | death_date = {{death date and age|df=yes|2015|01|06|1928|02|19}} | death_place = Cape Town, [[South Africa]] | nationality = [[South Africa]]n | field = [[Welfare Economics]] | workplaces = [[Nedbank]] | alma_mater = [[St John's College, Cambridge]] (Pd.D.) <br />[[University of Cape Town]] (B.A.) | influences = [[Abram Bergson]] | influenced = | contributions = }} '''Johannes de Villiers Graaff''' (also known as '''Jan de Van Graaff''' or '''Jannie Graaff'''; 19 February 1928 &ndash; 6 January 2015) was a [[South Africa]]n [[Neoclassical economics|neoclassical]] welfare economist.<ref>''The Meaning of Social Efficiency'' by Louis Lefeber; Thomas Vietorisz – Review of Political Economy, 1465–3982, Volume 19, Issue 2, 2007, pp. 139–64</ref> He was a former chairman of [[Nedbank]]. Graaff was known for his work on [[optimal savings rates]]<ref>{{Cite web |url=https://www.scribd.com/doc/6943263/Growth-Theory |title=Growth Theory, p. 107 |access-date=2017-10-26 |archive-date=2015-02-19 |archive-url=https://web.archive.org/web/20150219184537/https://www.scribd.com/doc/6943263/Growth-Theory |url-status=dead }}</ref> and contributions to the creation of the [[social welfare function]].<ref>{{Cite web |url=http://homepage.newschool.edu/het/essays/paretian/paretosocial.htm#swf |title=The Paretian System IV – Social Welfare |access-date=2015-01-15 |archive-date=2011-01-01 |archive-url=https://web.archive.org/web/20110101032249/http://homepage.newschool.edu/het/essays/paretian/paretosocial.htm#swf |url-status=dead }}</ref> Graaff graduated from the [[University of Cape Town]] and then went on to complete his PhD in economics at [[St John's College, Cambridge]] in 1950. On