This is a very important article about election prediction. Of course, you have to be a historian to make a proper judgement with a deep understanding of the underlying process. It is evaluated by human, not machine.
His simple linear regression beats all modern machine learning algorithms today!
The Keys to the White House, developed by Allan Lichtman, is a system for predicting the popular-vote result of American presidential elections, based upon the theory of pragmatic voting. America’s electorate, according to this theory, chooses a president, not according to events of the campaign, but according to how well the party in control of the White House has governed the country. If the voters are content with the party in power, it gains four more years in the White House; if not, the challenging party prevails. Thus, the choice of a president does not turn on debates, advertising, speeches, endorsements, rallies, platforms, promises, or campaign tactics. Rather, presidential elections are primarily referenda on the performance of the party holding the White House.
V = 37.2 + 1.8 * True = 37.2 + 1.8 * 7 = 49.7
Reference: Keys to the White House