Political scientists and historians differ on when Americans began using yard signs, but it's been nearly two centuries. John Quincy Adams had signs printed for his campaign for the presidency in 1824.
Experts say the current wire-frame versions began appearing in the 1960s as suburbs β and lawns β sprouted. Their usefulness is questionable, but Donald Green, a professor of political science at Columbia University, says his latest research, published this past March, suggests signs could provide a 1 to 2 percentage point boost to a candidate in a very tight contest β though he doubts they'd be a deciding factor in the race for the White House.
"They're not enormously effective, but they're not ineffective, either," Green says. "They could kick you over the line in a very tight race."
