There have been four “wrong winner” elections out of the nation’s 57 presidential elections between 1789 and 2012—a failure rate of 1 in 14.
Moreover, about half of American presidential elections are popular-vote landslides (i.e., those in which the winner’s nationwide margin is greater than 10%). Among the non-landslide elections, the failure rate for the current system is 1 in 7.
Although landslide presidential elections were common for much of the 20th century, the nation currently appears to be in an era of consecutive non-landslide presidential elections (1988, 1992, 1996, 2000, 2004, 2008, and 2012).
Therefore, it should not be surprising that there has been one “wrong winner” election in the recent string of seven non-landslide presidential elections between 1988 and 2012.
If the country continues to experience non-landslide presidential elections, we can expect additional “wrong winner” elections in the future.
An article on July 24, 2012, by Nate Silver in the New York Times, entitled “State and National Polls Tell Different Tales About State of Campaign”