Election forecasters try to bring some order to a chaotic political year

One model, by Robert Erikson of Columbia University and Chris Wlezien of the University of Texas, points to Clinton winning with 52 percent of the two-party popular vote. (Actual vote percentages for Clinton and Trump will be lower because of the presence of Libertarian Gary Johnson and the Green Party’s Jill Stein on the ballot.) That model combines post-convention polls with the results from the index of leading economic indicators.

Michael Lewis-Beck of the University of Iowa and Charles Tien of Hunter College also see a Clinton victory, with just 51 percent of the two-party popular vote. Tien said that translates to a narrow electoral college majority for Clinton of 274 votes.

Andreas Graefe of LMU Munich and J. Scott Armstrong of the Wharton School at the University of Pennsylvania cite four different models, all of which point to a victory by Clinton larger than some of the other forecasts.

One outlier is Helmut Norpoth of Stony Brook University. His model takes into account sentiment for a change in parties, but most important, and unusual, is his reliance on performance by the major-party candidates during the early presidential primaries, in this case New Hampshire and South Carolina. On that basis, he predicted last spring that Trump would win the election and said the prediction came with an 87 percent certainty.