Showing posts from April, 2012

Dewey beat Truman again

thanks to wikipedia Everyone who has ever had anything to do with the social research or polling industry will have heard the story about how all the opinion polls were so positive that Thomas Dewey was going to defeat Harry Truman in the 1948 US presidential election that the Chicago Tribune declared Dewey the winner the morning after the election.   The reason this happened, say opinion pollsters, is that the polls predicting a republican victory were done by telephone, and failed to account for democratic voters being less likely to  have telephones than republicans, telephones still being a luxury in 1948.   This is not necessarily a problem if  pollsters know that say, 90% of the  republican voters have telephones vs 80% of the population that vote democrat.  If this is known, mathematical adjustments are applied, and the poll becomes more accurate.  Because the results were so embarrassing, they figured out what they did wrong, and opinion polling has been fairly accurate