Eric Foner got a roaring response from a large crowd gathered to hear about the ratings of presidents -- and why they're a parlor game and nothing more. He recalled that the libertarians came up with a rating system a few years ago that ranked presidents on the basis of their budget expenditures. Those who increased the budget the least came out on top. In their poll Harding was first, Andrew Johnson was second, and Lincoln came in dead last. Foner noted that the famous Schlesinger polls (by both Sr. and Jr.) were also flawed. Both Schlesingers consulted mainly white men. The 1992 poll conducted by Schlesinger Jr. included a single African American and a single woman. Foner speculated that if more black scholars were included the ranking of Woodrow Wilson would not have been nearly as high on account of the Virginia[n]'s notorious racism. One historian enjoyed Foner's presentation so much he said he would have paid admission to get in.
BTW, if you have any taste for history, Foner's Reconstruction 1863-1877 is a must-read.