The 2018 Presidents & Executive Politics Presidential Greatness Survey was conducted by Brandon Rottinghaus and Justin S. Vaughn, who surveyed current and recent members of the Presidents & Executive Politics Section of the American Political Science Association and received 170 usable responses between Dec. 22, 2017 and Jan. 16, 2018. Note that while President Trump is making his debut on this poll at the bottom of the list, he took office on Jan. 20, 2017, after the poll was conducted. Trump and all the former US Presidents were rated on a scale of 0-100 for their "overall greatness." Abraham Lincoln scored the highest with an average rating of 95.03, while Donald Trump scored the lowest with an average rating of 12.34. The results were published at sps.boisestate.edu.
Poll of several hundred members of the American Political Science Association by the Brookings Institution; Brandon Rottinghaus and Justin S. Vaughn, "Measuring Obama against the Great Presidents," brookings.edu, Apr. 2, 2015
Participants were 238 "presidential scholars, historians and political scientists;" "Presidents 2010 Rank by Category," www.siena.edu, July 1, 2010
Participants were 65 "presidential historians" and "other professional observers of the presidency;" "C-SPAN 2009 Historians Presidential Leadership Survey," www.c-span.org, 2009
Participants were 8 correspondents, editors, bureau chiefs, columnists, and writers of The Times; "Who's the Greatest? The Times US Presidential Rankings," by Jeremy Griffin and Nico Hines, www.timesonline.co.uk, Oct. 28, 2008
Because of the short durations of their terms, William Henry Harrison and James Garfield were excluded from this ranking; participants were 85 "professors of history, law, political science and economics... the presidents are ranked in order of mean score, adjusted to give equal weight to Democratic- and Republican-leaning respondents;" "The Rankings," www.opinionjournal.com, Sep. 12, 2005
Participants were 32 "historians and close observers of presidential leadership;" "Rating the Presidents: Washington to Clinton," by Arthur M. Schlesinger, Jr., Political Science Quarterly, Summer 1997