Polling measures public sentiment using a relatively small sample of the population.
Polling works because it has been proven that a randomly selected sample, based on certain mathematical formulations, will accurately reflect a larger population's opinion.
The formulas used insure that every individual in a population has an equal chance of being selected for the sample. This is called random sampling.
Catholic University Libraries subscribes to two online polling resources: IPoll, produced by the Roper Center for Public Opinion Research (1935-); and Polling the Nations, produced by ORS Publishing (1986-).
iPoll surveys consist of national samples conducted by well-known organizations such as Gallup, Harris, Pew Research, etc. Samples usually consist of U.S. adults, 18 years or older
Polling the Nations is a much smaller database that iPoll; however, it is more likely to have surveys from organizations such as the Boy Scouts, the Red Cross, Catholic Church, etc. Polling the Nations has state surveys, and Internet surveys (IPoll has very few Internet surveys).
The first option on this list, Political Science Databases, will present you with a list of Political Science databases, which includes ipoll and Polling the Nations.