In a ranking of the power of the governorship in all 50 states, University of North Carolina political scientist Thad Beyle makes the distinction between "personal powers" of governors, which are factors that vary from person to person, season to season - and the "institutional powers" that are set in place by law. Examples of measurable personal factors are how large a governor's margin of victory was on election day, and where he or she stands in public opinion polls. Whether a governor has strong budget controls, appointment authority, and veto powers are examples of institutional powers.