Some of the quantitative methods are: the survey method, interview, questionnaire, etc.
Survey method is a data-gathering method with norms or rules, as laid down by Gallop and other pollsters, to forecast election results. General survey consists of data-collecting of the whole population of a country: it is called a census. It is the usual method adopted by the governments to collect, every ten years or so, information about the whole population. But in Political Science, a more limited survey is undertaken, called sample survey.
In a sample survey, a small group of peode, such as a certain number of voters, etc., are first selected, say about 2000 in number. They are then interviewed by trained interviewers in order to find out their opinions about the candidates or parties in the elections to be held in near future. The opinions thus collected constitute the data. The data is properly classified and computed in order to determine the probable results or forecast the results of the elections yet to be held.
It is necessary to observe certain norms or rules, if die survey method is to predict the election results fairly accurately. First of all, die sample must be representative of the national situation. The 2000 or so people chosen must be taken proportionately from among the poorer and richer classes, and also other criteria would be kept in view so that the “picture” of the national opinion should not be distorted.
Secondly, a sample survey should be undertaken a week or so before the elections, because opinion of the people (voters) is liable to change, especially if the interval is too long. Thirdly, the number of the people chosen for the sample should not be more than ten thousand and less than one thousand. If it is too large, it will become a census, and if too small, it will cease to be representative of the national public opinion.
Lastly, the sample may be undertaken by the Quota or random samples. The random sampling is favoured by political scientists and statisticians, while the quota sampling is undertaken by market research agencies. In random sampling the people are selected at random, but in quota sampling the number of people are first selected and then interviewed.
The survey method has been in use in the USA and Great Britain since long, but in a regular manner from about 1935. It is known as pollstering. In 1935, George Gallup established his American Institute erf Public Opinion to conduct weekly polls on current issues, using systematically selected but very small national samples of around 3000 respondents. A number of other organisations adopted similar methods in the U.S.A, including the Crossley poll and the Fortune survey. In the 1936 presidential election, Gallup Poll successfully predicted Roosevelt’s victory, which made the Gallup method very popular among the pollsters. Soon after, in 1937 Gallup set up a branch of his Institute in Great Britain, known as the British Institute of Public Opinion.
Afterwards Gallup established a chain of Gallup institutes in several countries of the world.