题目内容
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The first pre-election poll, or straw vote, as it was then called, was conducted by the Ha
Before the 1928 elections, no fewer than 85 publications made private inquires, generally by means of questionnaires sent to subscribers and by telephone surveys. The principle common to all these inquiries was that they depended on quantity rather than quality; little effort was made to reach representatives of all segments of the population. Still, the erroneous belief persisted that the greater the number of questionnaires, the more accurate the results would be. The record was held by the American monthly Literary Digest, which sent out millions of postcards with short and pointed questions before each election and received many hundreds of thousands of replies. In fact, in 1932, the Literary Digest's forecast was off by only 1%.
In view of such striking achievements, it seemed rather impertinent for the young American journalist, George Gallup, to claim that large numbers were irrelevant and that equally accurate or better predictions could be made with a small but carefully selected sample of the population and a small team of skilled interviewers.
In 1936, it took Gallup a long time to convince 35 newspaper editors that his system was much cheaper than the customary mass inquiries and that it could provide surprisingly accurate predictions. The editors finally agreed, on condition that if Gallup's predictions were less accurate than those obtained by the tried method of the Literary Digest, he would have to refund the entire cost of the investigation. Although the Literary Digest broke its own record by obtaining 2 million replies to its electoral postcards that year, its prediction was wrong by 19%, whereas Gallup's was off .by less than 1%.
Moreover, the Digest had predicted that Alfred M. Landon, the Republican candidate would obtain 56% of the votes cast, whereas Franklin D. Roosevelt was, in fact, re-elected with an unusually large majority. Gallup was one of the few political prophets who predicted this result.
Suddenly Gallup's name was on everyone's lips, not only was he the prophet of the moment, but it was generally conceded that he had found a new and most important scientific method of prediction. He was showered with money and commissions, and the Gallup Poll became a generic term for public opinion polls.
Unlike earlier prophets, Gallup based his investigations on sociological rather than purely arithmetical calculations. He realised that the electorate is made up of different social strata with differing political trends. Thus, farmers do not vote in the same way that industrial workers do, the North votes quite unlike the South, Black preferences vary from those of White persons, the interests of employers are different from those of employees, and so on. There are also voting differences according to age and sex, for it appeared that older people and women tend to vote for conservative parties.
Gallup usually sampled his subjects according to six factors: state, size of community, age, sex, income, and political affiliation. From time to time, other factors may be considered; during times of war, for instance, the national origins of electors may be taken into account.
Only when the composition of the electorate has been accurately determined can the purely arithmetical question-how many people in each bracket must be interviewed-be solved. Once this is done, laws of probabilities take over and the more people interviewed, the more exact the estimates will be. However,
A．is based merely on sociological calculations
B．can always predict accurate results
C．has been used in other countries other than the US
D．has become the best choice in predicting scientific results
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