Accuracy

Presidential model

Congress Compass has lowest average marginal error in swing states overall (2.45 percent) and the lowest individual error in seven of eight swing states for the 2020 U.S. presidential election. The forecast was only 1.0 percent off in Pennsylvania and 0.5 percent off in Michigan, despite other prognosticators missing the mark in these states by 3.5 to 5.0 percent and 4.9 to 5.6 percent respectively.

Congress Compass also had the most accurate prediction for the national popular vote margin and the lowest average marginal error for all states versus all other polling models that covered the 50 states and the District of Columbia, such as FiveThirtyEight and The Economist.

Congressional model

For the 2018 midterm elections, the Congress Compass forecast correctly called 96.8 percent (420 of 434) of the certified races for the House of Representatives. The race for overall control of the lower chamber was competitive, with 44 races decided by 5 percent or less and 80 races decided by less than 10 percent overall. However, the model correctly predicted 83.8 percent of these competitive races as well.