GMAT : Analysis of An Argument
81. 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 you find this argument. In your discussion be sure to analyze the line of reasoning and the use of evidence in the argument. For example, you may need to consider what questionable assumptions underline the thinking and what alternative explanations or counterexamples might weaken the conclusion. You can also discuss what sort of evidence would strengthen or refute the argument, what changes in the argument would make it more logically sound and what, if anything, would help you better evaluate in conclusion.
In this editorial the author asserts that opinion polls are little better than random guesses in predicting outcomes of presidential elections.
The author's 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 voting some remaining undecided until the moment they cast their vote.
The author's 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, in order to be random, 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 voter's mind and thereby increase the likelihood that the prediction based on them will be correct.
In addition, while it is true that many voters change their minds several times before voting and that some remain undecided until entering the voting booth, this is not true of everyone. Moreover, people who do change their minds frequently or wait until the last moment to decide have typically narrowed their choice to a few candidates.
In conclusion, the author is mistaken in believing that random guessing would be as reliable as opinion polls in predicting the outcomes of presidential elections.