This is a method pollsters commonly use to make a random selection within households without having to ask the respondent to provide a complete roster of adults living in the household.
Gallup does not use the same respondent selection procedure when making calls to cell phones because they are typically associated with one individual rather than shared among several members of a household. When respondents to be interviewed are selected at random, every adult has an equal probability of falling into the sample.
Gallup's Daily tracking process now allows Gallup analysts to aggregate larger groups of interviews for more detailed subgroup analysis. But the accuracy of the estimates derived only marginally improves with larger sample sizes. After Gallup collects and processes survey data, each respondent is assigned a weight so that the demographic characteristics of the total weighted sample of respondents match the latest estimates of the demographic characteristics of the adult population available from the U.
Gallup conducted interviews in Spanish for respondents who were primarily Spanish-speaking. The number of U. Since the U. Poll began in , Gallup conducted the survey every day, excluding major holidays and other events, for days per year, through the end of Before , there were daily quotas of completes.
Yes, Gallup weighted samples to correct for unequal selection probability, nonresponse, and double coverage of landline and cellphone users in the two sampling frames. Gallup also weighted its final samples to match the U. Demographic weighting targets for the U. Phone status targets were based on the most recent National Health Interview Survey. Population density targets were based on the most recent U. All reported margins of sampling error included computed design effects for weighting.
Gallup reported findings from the survey on News. Gallup also reported U. Poll results in interactive features such as:. Although George Gallup did not invent public opinion polling, he virtually created the image of the 'pollster. The scores of pollsters that today work in politics, as well as market research, owe a debt of gratitude to his pioneering efforts.
Political polls were conducted in America long before Gallup. The first published presidential poll, based on a straw vote, appeared on July 24, in the Harrisburg Pennsylvanian.
Newspapers at the time were little more than vehicles for the political parties, but as economic pressures forced publishers to become less partisan in order to expand readership, objectivity became a virtue.
Straw polls were, by definition, objective; and by the beginning of the 20th century they became a staple of newspapers. The way straw polls were conducted, however, did not lend itself to accuracy. Some newspapers and magazines printed the ballot within its pages. Readers mailed in or hand delivered their votes, and they were encouraged to stuff the ballot box by purchasing more copies of the publication. Reliable results were willingly sacrificed for a spike in sales. A later technique, the mail ballot, selected names from such sources as telephone directories, registered voter lists, and automobile registrations.
Then a 'sample' was created by pulling names at certain intervals, such as every tenth one. It was more difficult to stuff the ballot box, but the sample had an inherent bias against the lower economic strata. The 'personal canvass' proved to be the most reliable method for conducting straw votes. Under this method, 'solicitors' would hand out pencils and ballots to people on the street and collect the votes on the spot. Some newspapers made an attempt to sample a cross section of voters by creating quotas for their solicitors, for example requiring a certain number of white-collar voters from one community and blue-collar voters from another.
Although arrived at intuitively, this technique anticipated the scientific polling that Gallup and others would refine. Most of the early newspaper polls were local or regional. The New York Herald Tribune and collaborating newspapers began to conduct wider pre-election polls in the s. By they polled in over 35 states. The Hearst newspapers attempted nationwide polling in Forty-three states were covered, but the average error rate was a high six percent.
In , however, Hearst had an error rate of less than three points in 46 states. By the s the publication with the greatest reputation for accurate polling was the Literary Digest-- the Time or Newsweek of its day. The Digest mailed out an incredible 20 million ballots and covered all 48 states. Although some critics questioned the sample, maintaining that the Digest overemphasized the higher income brackets, the results of the election silenced all doubters.
The straw poll predicted a Franklin Roosevelt win with The election results gave Roosevelt the win with The straw poll also predicted that Roosevelt would win 41 states, totaling electoral votes. The actual results were 42 states and electoral votes. The Literary Digest did not hesitate to crow about its accomplishment and was now more than a little confident in its ability to predict election results.
Then in the summer of , more than six weeks before the Digest began its massive mailing to poll for the winner of the Roosevelt-Alf Landon presidential race, a little-known pollster from Princeton, New Jersey, predicted that the Digest would be wrong, and he had the further audacity to predict their final numbers.
That pollster was George Gallup. Gallup attended the University of Iowa, where he became editor of the campus newspaper. While working one summer for a St. Louis advertising agency that was researching reader satisfaction with the St. Louis Post-Dispatch , Gallup decided that there had to be a more efficient way to measure opinions than to go door to door, neighborhood after neighborhood.
He wondered if he could use techniques similar to the ones employed by government inspectors who might test a crop of wheat or a supply of water by taking several small samples then extrapolate the quality of the entire amount.
While teaching journalism at Iowa, Gallup earned his M. In he was hired by the New York advertising agency of Young and Rubicam as director of research. He would work for the company until It was also in that Gallup's mother-in-law was elected Iowa's Secretary of State, under unusual circumstances.
She had been placed on the ballot in honor of her husband who had died during a run for governor in Despite running as a Democrat in a heavily Republican state, and without even mounting a campaign, she was swept into office with a Roosevelt landslide.
0コメント