Historian polls assume greater factual knowledge yields more objective ratings

Evidence

One approach to measuring presidential greatness is to rely on the judgments of scholars of American history. Although their judgments are undoubtedly affected by their values, historians are presumably in possession of more facts than are most people and are in a better position to make objective evaluations and comparative ratings. Over the past 35 years, historians have often been polled on presidential greatness. — John T. Jost and Jim Sidanius, Political Psychology, 1346