The Economist’s model of America’s presidential election estimates each major candidate’s chances of winning each state and the overall electoral college. Developed with a team of scholars at Columbia University, the forecast combines national and state-level polls with fundamental data about the state of the economy, historical voting patterns and the demographics of each state to predict the likelihood of various outcomes of the race. The model does this by constructing thousands of scenarios, each one containing different vote shares in each state and different values for the impact of polling biases and other characteristics. The model is more likely to generate scenarios that are closer to matching the polls and fundamental data it has been given. The win probabilities presented here represent the share of these scenarios won by each candidate.”

Our model is updated every day and combines state and national polls with economic indicators to predict the election results across the country. To work out the probable electoral-vote totals, we run over 10,000 simulations of the election. The chance of a tie in the electoral college is less than 1 in 100…”