The following appeared in the editorial section of a daily newspaper.
Although forecasts of presidential elections based on opinion polls measure current voter preference, many voters keep changing their minds about whom they prefer until the last few days before the balloting. Some do not even make a final decision until they enter the voting booth. Forecasts based on opinion polls are therefore little better at predicting election outcomes than a random guess would be.
Discuss how well reasoned... etc.
In this editorial the author asserts that opinion polls are little better than random guesses to predicting outcomes of presidential elections. The authors basis for this assertion is that opinion polls measure only the preferences of voters at the time of the poll and that many voters change their preferences several time before votingsome remaining undecided until the moment they cast their vote. The authors reasoning is unconvincing in two critical respects.
First of all the predictions based on random guessing are such that the greater the number of candidates, the less likely the prediction will be correct. The reason for this is obvious: random guessing requires that no outside information be allowed to influence the guess. Predictions based on opinion polls, on the other hand, will differ considerably from those based on random guesses simply because outside information will influence the result. For example, in a four-person race, random guessing would yield the correct prediction 25 percent of the time, whereas the percentage of correct predictions based on opinion polls would be much higher. The reason for this disparity is simple. Opinion polls enable us to narrow the choices. That is, opinion polls serve to reduce the number of viable candidates in the voters mind and thereby increase the likelihood that the prediction based on them will be correct.
