Gallup Poll is an organization that conducts public opinion polling in a regular basis throughout one hundred and forty countries around the world. It has a reputation of being the most trustworthy and accurate in depicting the public opinions on various kinds of issues. It is also best known for the accuracy in predicting the United States presidential elections results.
In conducting a public opinion poll, the first and foremost important concept is the basic principle of probability sampling, or at least that is what Gallup values as an important foundation. The probability sampling itself holds the definition as “a sampling technique wherein the samples are gathered in a process that gives all individuals in the population equal chances of being selected” (Castillo). With the probability sampling technique, every individual is guaranteed to have an equal opportunity of being selected by using the randomization technique. The concept is then specified as “equal probability of selection” or EPS, whereas every element in the population has the same probability (or non-zero chance) of selection. EPS does not necessarily means that every unit at every stage has the same probability of being selected. It rather indicates that every unit is actually included in the sample has the same probability of being selected in advance of sampling. Simply put, no one is left out and no one is favored (Frerichs 1-2).
The whole concept of probability sampling cannot be separated from the utilization of random sampling. It is typically used to achieve an unbiased sample, where again, each subject or unit in the population will have an equal chance of being selected. In order to obtain a true random sample, the key point is randomization. We need to go through the process of identifying the target population, get a representative sample of that target population, which can be obtained from a sampling frame. A sampling frame is a list or something
Cited: Castillo, Joan Joseph. "Probability Sampling and Randomization." Experiment Resources. N.p., 2009. Web. 17 July 2012. <http://www.experiment-resources.com/probability-sampling.html#ixzz217GxG18m>. Newton, Frank, Lydia Saad, and David Moore. "How Are Polls Conducted." 1997. Digital file. Frerichs, R. R. "Equal Probability of Selection." 2004. MS. Saad, Lydia. "U.S. Perceptions of Job Market Remain Weak but Improved." Gallup. N.p., 13 June 2012. Web. 18 July 2012. <http://www.gallup.com/poll/155171/Perceptions-Job-Market-Remain-Weak-Improved.aspx>.