Fair, 67, wrote his first paper on an equation to predict election outcomes in 1978. He refined the theory before revamping it in 1992 after failing to predict that year's presidential election.
Since then, Fair said, "the presidential vote equation has done reasonably," accurately predicting each election. In 2008, he came within 1.1 percentage point of Barack Obama's victory margin over Republican John McCain.
During the 2008 elections, Fair also developed his congressional vote equation.
Clinton, Reagan
Low presidential approval ratings in opinion polls can translate into big congressional losses. Former President Bill Clinton's Democratic Party lost 54 House seats in the 1994 congressional elections when his public approval rating was 39% two months before the election. Ronald Reagan's 42% approval rating was followed by Republican losses of 26 seats in 1982.
Democrats in 1982 beat Republicans in the national vote cast in congressional elections by 12 percentage points. In 1994, Republicans bested Democrats by 7 points.
Obama's approval rating has hovered around 50% for much of this year in Gallup's three-day average. It was 46% as of Sept. 6; the record low was 41% last month.
White House Press Secretary Robert Gibbs dismissed the opinion surveys.
"The American people are not concerned about the president's poll numbers," Gibbs told reporters at a White House briefing yesterday.
Economic Numbers Set
Though Fair's latest figures are from July 30, he said he doesn't expect his final pre-election estimate at the end of October to shift his prediction for the outcome of the midterms.