Skip to main content
No. 1199:
Gallup Poll

Today, we try to foretell how you plan to vote. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

If I say Gallup Poll, what image flashes in your mind? You see Harry Truman, smiling and victorious after the 1948 presidential election. He holds a copy of the Chicago Daily Tribune with the headline "Dewey Defeats Truman." Gallup is best known for that one half-century-old blunder. There's a terrible irony in that. The studious George Gallup did more than anyone to put opinion polling on solid ground.

Let's go to back to the Landon-Roosevelt race in 1936. Thirty-five-year-old George Gallup was running a fledgling polling service. He'd begun his career by advising newspapers on how readers used their papers. Gallup had written both master's and doctoral theses on the psychology of marketing. He'd gone on to become a journalism professor at Northwestern University. Then a New York advertising agency hired him out of academia.

Political polls were 130 years old by then. The expression "straw poll" goes back to rural America where it derived from another old saying, "straws in the wind." A farmer once threw a handful of straws into the air to see which way the wind was blowing. In the 1820s, newspapers began doing straw polls in the streets to see how political winds blew.

Gallup brought science to that process. Richard Smith tells how, by the time Landon challenged Roosevelt, the prestigious Literary Digest magazine was America's leading pollster. The Digest featured a regular poll called "America Speaks." It drew samples from phone books and auto registrations. Gallup knew that such samples were biased toward people with means. I remember life in those days: not everyone could afford cars or phones. My parents, who had both, strongly supported the Republican Landon.

So the Digest predicted a solid victory for Landon. Using a far smaller, far better sample, Gallup predicted Roosevelt's victory. He did more than that. He also showed why the Digest's flawed methods predicted Landon would win. In the wake of that, the Digest folded up, and Gallup became America's oracle.

Then, in 1948, Gallup blew the Truman-Dewey prediction. How? His mistake was to quit polling two weeks before the election with fourteen percent of the electorate still undecided. After that humiliation, Gallup went back to analyze his error. He emerged with the maxim, "Undecided voters side with the incumbent."

Unlike the Literary Digest, Gallup bounced back, and his polls flourish today. Meanwhile, every trailing politician since 1948 has promised to do what Truman did, but few actually have. And yet Gallup's great gaffe was a fine legacy. It reminded us that the best oracle cannot be trusted absolutely. The stars do not control our lives, and it is never completely over -- until it's over.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

Smith, R. D., Letting America Speak. Audacity, Winter 1997, pp. 50- 61. I'm grateful to Roger Eichhorn, UH Mechanical Engineering Department, for providing this source.